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1 1
2 2
3 3 .. _`nbconvert script`:
4 4
5 5 Converting notebooks to other formats
6 6 =====================================
7 7
8 8 Newly added in the 1.0 release of IPython is the ``nbconvert`` tool, which
9 9 allows you to convert an ``.ipynb`` notebook document file into various static
10 10 formats.
11 11
12 12 Currently, ``nbconvert`` is provided as a command line tool, run as a script
13 13 using IPython. In the future, a direct export capability from within the
14 14 IPython Notebook web app is planned.
15 15
16 16 The command-line syntax to run the ``nbconvert`` script is::
17 17
18 18 $ ipython nbconvert --format=FORMAT notebook.ipynb
19 19
20 20 This will convert the IPython document file ``notebook.ipynb`` into the output
21 21 format given by the ``FORMAT`` string.
22 22
23 23 The default output format is HTML, for which the ``--format`` modifier may be
24 24 omitted::
25 25
26 26 $ ipython nbconvert notebook.ipynb
27 27
28 28 The currently supported export formats are the following:
29 29
30 30 * HTML:
31 31
32 32 - **full_html**:
33 33 Standard HTML
34 34
35 35 - **simple_html**:
36 36 Simplified HTML
37 37
38 38 - **reveal**:
39 39 HTML slideshow presentation for use with the ``reveal.js`` package
40 40
41 41 * PDF:
42 42
43 43 - **sphinx_howto**:
44 44 The format for Sphinx_ HOWTOs; similar to an ``article`` in LaTeX
45 45
46 46 - **sphinx_manual**:
47 47 The format for Sphinx_ manuals; similar to a ``book`` in LaTeX
48 48
49 49 - **latex**:
50 50 An article formatted completely using LaTeX
51 51
52 52 * Markup:
53 53
54 54 - **rst**:
55 55 reStructuredText_ markup
56 56
57 57 - **markdown**:
58 58 Markdown_ markup
59 59
60 60 .. _Sphinx: http://sphinx-doc.org/
61 61 .. _reStructuredText: http://docutils.sourceforge.net/rst.html
62 .. _Markdown: http://daringfireball.net/projects/markdown/syntax
62 63
63 64 * Python:
64 65
65 66 Comments out all the non-Python code to produce a ``.py`` Python
66 67 script with just the code content. Currently the output includes IPython
67 68 magics, and so can be run with ``ipython``, after changing the extension
68 69 of the script to ``.ipy``.
69 70
70 71 The files output file created by ``nbconvert`` will have the same base name as
71 72 the notebook and will be placed in the current working directory. Any
72 73 supporting files (graphics, etc) will be placed in a new directory with the
73 74 same base name as the notebook, suffixed with ``_files``::
74 75
75 76 $ ipython nbconvert notebook.ipynb
76 77 $ ls
77 78 notebook.ipynb notebook.html notebook_files/
78 79
79 80 Each of the options for PDF export produces as an intermediate step a LaTeX
80 81 ``.tex`` file with the same basename as the notebook, as well as individual
81 82 files for each figure, and ``.text`` files with textual output from running
82 83 code cells.
83 84
84 85 To actually produce the final PDF file, run the following commands::
85 86
86 87 $ ipython nbconvert --format=latex notebook.ipynb
87 88 $ pdflatex notebook
88 89
89 90 This requires a local installation of LaTeX on your machine.
90 91 The output is a PDF file ``notebook.pdf``, also placed inside the
91 92 ``nbconvert_build`` subdirectory.
92 93
93 94 Alternatively, the output may be sent to standard output with::
94 95
95 96 $ ipython nbconvert notebook.ipynb --stdout
96 97
97 98 Multiple notebooks can be specified from the command line::
98 99
99 100 $ ipython nbconvert notebook*.ipynb
100 101 $ ipython nbconvert notebook1.ipynb notebook2.ipynb
101 102
102 103 or via a list in a configuration file, say ``mycfg.py``, containing the text::
103 104
104 105 c = get_config()
105 106 c.NbConvertApp.notebooks = ["notebook1.ipynb", "notebook2.ipynb"]
106 107
107 108 and using the command::
108 109
109 110 $ ipython nbconvert --config mycfg.py
110 111
111 112
112 113 Extracting standard Python files from notebooks
113 114 -----------------------------------------------
114 115 ``.ipynb`` notebook document files are plain text files which store a
115 116 representation in JSON format of the contents of a notebook space. As such,
116 117 they are not valid ``.py`` Python scripts, and so can be neither imported
117 118 directly with ``import`` in Python, nor run directly as a standard Python
118 119 script (though both of these are possible with simple workarounds).
119 120
120 121
121 122 To extract the Python code from within a notebook document, the simplest
122 123 method is to use the ``File | Download as | Python (.py)`` menu item; the
123 124 resulting ``.py`` script will be downloaded to your browser's default
124 125 download location.
125 126
126 127 An alternative is to pass an argument to the IPython Notebook, from the moment
127 128 when it is originally started, specifying that whenever it saves an ``.ipynb``
128 129 notebook document, it should, at the same time, save the corresponding
129 130 ``.py`` script. To do so, you can execute the following command::
130 131
131 132 $ ipython notebook --script
132 133
133 134 or you can set this option permanently in your configuration file with::
134 135
135 136 c = get_config()
136 137 c.NotebookManager.save_script=True
137 138
138 139 The result is that standard ``.py`` files are also now generated, which
139 140 can be ``%run``, imported from regular IPython sessions or other notebooks, or
140 141 executed at the command line, as usual. Since the raw code you have typed is
141 142 exported, you must avoid using syntax such as IPython magics and other
142 143 IPython-specific extensions to the language for the files to be able to be
143 144 successfully imported.
144 145 .. or you can change the script's extension to ``.ipy`` and run it with::
145 146 ..
146 147 .. $ ipython script.ipy
147 148
148 149 In normal Python practice, the standard way to differentiate importable code
149 150 in a Python script from the "executable" part of a script is to use the
150 151 following idiom at the start of the executable part of the code::
151 152
152 153 if __name__ == '__main__'
153 154
154 155 # rest of the code...
155 156
156 157 Since all cells in the notebook are run as top-level code, you will need to
157 158 similarly protect *all* cells that you do not want executed when other scripts
158 159 try to import your notebook. A convenient shortand for this is to define
159 160 early on::
160 161
161 162 script = __name__ == '__main__'
162 163
163 164 Then in any cell that you need to protect, use::
164 165
165 166 if script:
166 167 # rest of the cell...
167 168
168 169
169 170
170 171 .. _notebook_format:
171 172
172 173 Notebook JSON file format
173 174 -------------------------
174 175 Notebook documents are JSON files with an ``.ipynb`` extension, formatted
175 176 as legibly as possible with minimal extra indentation and cell content broken
176 177 across lines to make them reasonably friendly to use in version-control
177 178 workflows. You should be very careful if you ever manually edit this JSON
178 179 data, as it is extremely easy to corrupt its internal structure and make the
179 180 file impossible to load. In general, you should consider the notebook as a
180 181 file meant only to be edited by the IPython Notebook app itself, not for
181 182 hand-editing.
182 183
183 184 .. note::
184 185
185 186 Binary data such as figures are also saved directly in the JSON file.
186 187 This provides convenient single-file portability, but means that the
187 188 files can be large; a ``diff`` of binary data is also not very
188 189 meaningful. Since the binary blobs are encoded in a single line, they
189 190 affect only one line of the ``diff`` output, but they are typically very
190 191 long lines. You can use the ``Cell | All Output | Clear`` menu option to
191 192 remove all output from a notebook prior to committing it to version
192 193 control, if this is a concern.
193 194
194 195 The notebook server can also generate a pure Python version of your notebook,
195 196 using the ``File | Download as`` menu option. The resulting ``.py`` file will
196 197 contain all the code cells from your notebook verbatim, and all Markdown cells
197 198 prepended with a comment marker. The separation between code and Markdown
198 199 cells is indicated with special comments and there is a header indicating the
199 200 format version. All output is removed when exporting to Python.
200 201
201 202 As an example, consider a simple notebook called ``simple.ipynb`` which
202 203 contains one Markdown cell, with the content ``The simplest notebook.``, one
203 204 code input cell with the content ``print "Hello, IPython!"``, and the
204 205 corresponding output.
205 206
206 207 The contents of the notebook document ``simple.ipynb`` is the following JSON
207 208 container::
208 209
209 210 {
210 211 "metadata": {
211 212 "name": "simple"
212 213 },
213 214 "nbformat": 3,
214 215 "nbformat_minor": 0,
215 216 "worksheets": [
216 217 {
217 218 "cells": [
218 219 {
219 220 "cell_type": "markdown",
220 221 "metadata": {},
221 222 "source": "The simplest notebook."
222 223 },
223 224 {
224 225 "cell_type": "code",
225 226 "collapsed": false,
226 227 "input": "print \"Hello, IPython\"",
227 228 "language": "python",
228 229 "metadata": {},
229 230 "outputs": [
230 231 {
231 232 "output_type": "stream",
232 233 "stream": "stdout",
233 234 "text": "Hello, IPython\n"
234 235 }
235 236 ],
236 237 "prompt_number": 1
237 238 }
238 239 ],
239 240 "metadata": {}
240 241 }
241 242 ]
242 243 }
243 244
244 245
245 246 The corresponding Python script is::
246 247
247 248 # -*- coding: utf-8 -*-
248 249 # <nbformat>3.0</nbformat>
249 250
250 251 # <markdowncell>
251 252
252 253 # The simplest notebook.
253 254
254 255 # <codecell>
255 256
256 257 print "Hello, IPython"
257 258
258 259 Note that indeed the output of the code cell, which is present in the JSON
259 260 container, has been removed in the ``.py`` script.
260 261
@@ -1,564 +1,561 b''
1 1 .. _htmlnotebook:
2 2
3 3 The IPython Notebook
4 4 ====================
5 5
6 6 The IPython Notebook is part of the IPython package, which aims to provide a
7 7 powerful, interactive approach to scientific computation.
8 8 The IPython Notebook extends the previous text-console-based approach, and the
9 9 later Qt console, in a qualitatively new diretion, providing a web-based
10 10 application suitable for capturing the whole scientific computation process.
11 11
12 12 .. seealso::
13 13
14 14 :ref:`Installation requirements <installnotebook>` for the Notebook.
15 15
16 16
17 17 .. Basic structure
18 18 .. ---------------
19 19
20 20 Introduction
21 21 ------------
22 22
23 23 The IPython Notebook combines two components:
24 24
25 25 * **The IPython Notebook web application**:
26 26
27 27 The *IPython Notebook web app* is a browser-based tool for interactive
28 28 authoring of literate computations, in which explanatory text,
29 29 mathematics, computations and rich media output may be combined. Input
30 30 and output are stored in persistent cells that may be edited in-place.
31 31
32 32 * **Notebook documents**:
33 33
34 34 *Notebook documents*, or *notebooks*, are plain text documents which
35 35 record all inputs and outputs of the computations, interspersed with
36 36 text, mathematics and HTML 5 representations of objects, in a literate
37 37 style.
38 38
39 39 Since the similarity in names can lead to some confusion, in this
40 40 documentation we will use capitalization of the word "notebook" to
41 distinguish the *N*otebook app and *n*otebook documents, thinking of the
41 distinguish the Notebook app and notebook documents, thinking of the
42 42 Notebook app as being a proper noun. We will also always refer to the
43 43 "Notebook app" when we are referring to the browser-based interface,
44 44 and usually to "notebook documents", instead of "notebooks", for added
45 45 precision.
46 46
47 47 We refer to the current state of the computational process taking place in the
48 48 Notebook app, i.e. the (numbered) sequence of input and output cells, as the
49 49 *notebook space*. Notebook documents provide an *exact*, *one-to-one* record
50 50 of all the content in the notebook space, as a plain text file in JSON format.
51 51 The Notebook app automatically saves, at certain intervals, the contents of
52 52 the notebook space to a notebook document stored on disk, with the same name
53 53 as the title of the notebook space, and the file extension ``.ipynb``. For
54 54 this reason, there is no confusion about using the same word "notebook" for
55 both the notebook space and the corresonding notebook document, since they are
55 both the notebook space and the corresponding notebook document, since they are
56 56 really one and the same concept (we could say that they are "isomorphic").
57 57
58 58
59 59 Main features of the IPython Notebook web app
60 60 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
61 61
62 62 The main features of the IPython Notebook app include:
63 63
64 64 * In-browser editing for code, with automatic syntax highlighting and
65 65 indentation and tab completion/introspection.
66 66
67 67 * Literate combination of code with rich text using the Markdown_ markup
68 68 language.
69 69
70 70 * Mathematics is easily included within the Markdown using LaTeX notation, and
71 71 rendered natively by MathJax_.
72 72
73 73 * Displays rich data representations (e.g. HTML / LaTeX / SVG) as the result
74 74 of computations.
75 75
76 76 * Publication-quality figures in a range of formats (SVG / PNG), rendered by
77 77 the matplotlib_ library, may be included inline and exported.
78 78
79 79
80 80 .. _MathJax: http://www.mathjax.org/
81 81 .. _matplotlib: http://matplotlib.org/
82 82 .. _Markdown: http://daringfireball.net/projects/markdown/syntax
83 83
84 84
85 85 Notebook documents
86 86 ~~~~~~~~~~~~~~~~~~
87 87
88 Notebook document files are just standard, ASCII-coded text files with the
89 extension ``.ipynb``, stored in the working directory on your computer.
90 Since the contents of the files are just plain text, they can be easily
91 version-controlled and shared with colleagues.
92
93 Internally, notebook document files use the JSON_ format, allowing them to
94 store a *complete*, *reproducible*, *one-to-one* copy of the state of the
88 Notebook document files are simple JSON_ files with the
89 extension ``.ipynb``.
90 Since JSON is just plain text, they can be easily version-controlled and shared with colleagues.
91 The notebook stores a *complete*, *reproducible*, *one-to-one* copy of the state of the
95 92 computational state as it is inside the Notebook app. All computations
96 93 carried out, and the corresponding results obtained, can be combined in
97 94 a literate way, interleaving executable code with rich text, mathematics,
98 and HTML 5 representations of objects.
95 and rich representations of objects.
99 96
100 97 .. _JSON: http://en.wikipedia.org/wiki/JSON
101 98
102 99 Notebooks may easily be exported to a range of static formats, including
103 HTML (for example, for blog posts), PDF and slide shows, via the
104 newly-included `nbconvert script`_ functionality.
100 HTML (for example, for blog posts), PDF and slide shows,
101 via the new nbconvert_ command.
105 102
106 Furthermore, any ``.ipynb`` notebook document with a publicly-available
107 URL can be shared via the `IPython Notebook Viewer`_ service. This service
108 loads the notebook document from the URL which will
109 provide it as a static web page. The results may thus be shared with a
103 Furthermore, any ``.ipynb`` notebook document available from a public
104 URL can be shared via the `IPython Notebook Viewer <nbviewer>`_ service.
105 This service loads the notebook document from the URL and will
106 render it as a static web page. The results may thus be shared with a
110 107 colleague, or as a public blog post, without other users needing to install
111 IPython themselves.
108 IPython themselves. NbViewer is simply NbConvert as a simple heroku webservice.
112 109
113 110 See the :ref:`installation documentation <install_index>` for directions on
114 111 how to install the notebook and its dependencies.
115 112
116 .. _`Ipython Notebook Viewer`: http://nbviewer.ipython.org
113 .. _nbviewer: http://nbviewer.ipython.org
117 114
118 115 .. note::
119 116
120 117 You can start more than one notebook server at the same time, if you want
121 118 to work on notebooks in different directories. By default the first
122 119 notebook server starts on port 8888, and later notebook servers search for
123 120 ports near that one. You can also manually specify the port with the
124 121 ``--port`` option.
125 122
126 123
127 124 Basic workflow in the IPython Notebook web app
128 125 ----------------------------------------------
129 126
130 127 Starting up
131 128 ~~~~~~~~~~~~
132 129
133 130 You can start running the Notebook web app using the following command::
134 131
135 132 $ ipython notebook
136 133
137 134 (Here, and in the sequel, the initial ``$`` represents the shell prompt,
138 135 indicating that the command is to be run from the command line in a shell.)
139 136
140 137 The landing page of the IPython Notebook application, the *dashboard*, shows
141 the notebooks currently available in the *working directory* (the directory
138 the notebooks currently available in the *notebook directory* (By default, the directory
142 139 from which the notebook was started).
143 140 You can create new notebooks from the dashboard with the ``New Notebook``
144 141 button, or open existing ones by clicking on their name.
145 142 You can also drag and drop ``.ipynb`` notebooks and standard ``.py`` Python
146 143 source code files into the notebook list area.
147 144
148 145
149 146 You can open an existing notebook directly, without having to go via the
150 147 dashboard, with:
151 148
152 149 ipython notebook my_notebook
153 150
154 151 The `.ipynb` extension is assumed if no extension is given.
155 152
156 153 The `File | Open...` menu option will open the dashboard in a new browser tab,
157 154 to allow you to select a current notebook
158 from the working directory or to create a new notebook
155 from the notebook directory or to create a new notebook.
159 156
160 157
161 158
162 159 Notebook user interface
163 160 ~~~~~~~~~~~~~~~~~~~~~~~
164 161
165 162 When you open a new notebook document in the Notebook, you will be presented
166 163 with the title associated to the notebook space/document, a *menu bar*, a
167 164 *toolbar* and an empty *input cell*.
168 165
169 166 Notebook title
170 167 ^^^^^^^^^^^^^^
171 168 The title of the notebook document that is currently being edited is displayed
172 169 at the top of the page, next to the ``IP[y]: Notebook`` logo. This title may
173 170 be edited directly by clicking on it. The title is reflected in the name of
174 171 the ``.ipynb`` notebook document file that is saved.
175 172
176 173 Menu bar
177 174 ^^^^^^^^
178 175 The menu bar presents different options that may be used to manipulate the way
179 176 the Notebook functions.
180 177
181 178 Toolbar
182 179 ^^^^^^^
183 180 The tool bar gives a quick way of accessing the most-used operations within
184 181 the Notebook, by clicking on an icon.
185 182
186 183
187 184 Creating a new notebook document
188 185 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
189 186
190 187 A new notebook space/document may be created at any time, either from the
191 188 dashboard, or using the `File | New` menu option from within an active
192 notebook. The new notebook is created within the same working directory and
189 notebook. The new notebook is created within the same directory and
193 190 will open in a new browser tab. It will also be reflected as a new entry in
194 191 the notebook list on the dashboard.
195 192
196 193
197 194 Structure of a notebook document
198 195 --------------------------------
199 196
200 197 Input cells
201 198 ~~~~~~~~~~~
202 199 Input cells are at the core of the functionality of the IPython Notebook.
203 200 They are regions in the document in which you can enter different types of
204 201 text and commands. To *execute* or *run* the *current cell*, i.e. the cell
205 202 under the cursor, you can use the :kbd:`Shift-Enter` key combination.
206 203 This tells the Notebook app to perform the relevant operation for each type of
207 204 cell (see below), and then to display the resulting output.
208 205
209 206 The notebook consists of a sequence of input cells, labelled ``In[n]``, which
210 207 may be executed in a non-linear way, and outputs ``Out[n]``, where ``n`` is a
211 208 number which denotes the order in which the cells were executed over the
212 209 history of the computational process. The contents of all of these cells are
213 210 accessible as Python variables with the same names, forming a complete record
214 211 of the history of the computation.
215 212
216 213
217 214
218 215 Input cell types
219 216 ~~~~~~~~~~~~~~~~
220 217 Each IPython input cell has a *cell type*, of which there is a restricted
221 218 number. The type of a cell may be set by using the cell type dropdown on the
222 219 toolbar, or via the following keyboard shortcuts:
223 220
224 221 * **code**: :kbd:`Ctrl-m y`
225 222 * **markdown**: :kbd:`Ctrl-m m`
226 223 * **raw**: :kbd:`Ctrl-m t`
227 224 * **heading**: :kbd:`Ctrl-m 1` - :kbd:`Ctrl-m 6`
228 225
229 226 Upon initial creation, each input cell is by default a code cell.
230 227
231 228
232 229 Code cells
233 230 ^^^^^^^^^^
234 231 A *code input cell* allows you to edit code inline within the cell, with full
235 232 syntax highlighting and autocompletion/introspection. By default, the language
236 233 associated to a code cell is Python, but other languages, such as ``julia``
237 234 and ``R``, can be handled using magic commands (see below).
238 235
239 236 When a code cell is executed with :kbd:`Shift-Enter`, the code that it
240 237 contains is transparently exported and run in that language (with automatic
241 238 compiling, etc., if necessary). The result that is returned from this
242 239 computation is then displayed in the notebook space as the cell's
243 240 *output*. If this output is of a textual nature, it is placed into a
244 241 numbered *output cell*. However, many other possible forms of output are also
245 242 possible, including ``matplotlib`` figures and HTML tables (as used, for
246 243 example, in the ``pandas`` data analyis package). This is known as IPython's
247 244 *rich display* capability.
248 245
249 246
250 247 Markdown cells
251 248 ^^^^^^^^^^^^^^
252 249 You can document the computational process in a literate way, alternating
253 250 descriptive text with code, using *rich text*. In IPython this is accomplished
254 251 by marking up text with the Markdown language. The corresponding cells are
255 252 called *Markdown input cells*. The Markdown language provides a simple way to
256 253 perform this text markup, that is, to specify which parts of the text should
257 254 be emphasized (italics), bold, form lists, etc.
258 255
259 256
260 257 When a Markdown input cell is executed, the Markdown code is converted into
261 258 the corresponding formatted rich text. This output then *replaces* the
262 259 original Markdown input cell, leaving just the visually-significant marked up
263 260 rich text. Markdown allows arbitrary HTML code for formatting.
264 261
265 262 Within Markdown cells, you can also include *mathematics* in a straightforward
266 263 way, using standard LaTeX notation: ``$...$`` for inline mathematics and
267 264 ``$$...$$`` for displayed mathematics. When the Markdown cell is executed,
268 265 the LaTeX portions are automatically rendered in the HTML output as equations
269 266 with high quality typography. This is made possible by MathJax_, which
270 supports a `large subset`_ of LaTeX functionality
267 supports a `large subset <mathjax_tex>`_ of LaTeX functionality
271 268
272 .. _`large subset`: http://docs.mathjax.org/en/latest/tex.html
269 .. _mathjax_tex: http://docs.mathjax.org/en/latest/tex.html
273 270
274 271 Standard mathematics environments defined by LaTeX and AMS-LaTeX (the
275 272 `amsmath` package) also work, such as
276 273 ``\begin{equation}...\end{equation}``, and ``\begin{align}...\end{align}``.
277 274 New LaTeX macros may be defined using standard methods,
278 275 such as ``\newcommand``, by placing them anywhere *between math delimiters* in
279 276 a Markdown cell. These definitions are then available throughout the rest of
280 277 the IPython session. (Note, however, that more care must be taken when using
281 the `nbconvert script`_ to output to LaTeX).
278 nbconvert_ to output to LaTeX).
282 279
283 280 Raw input cells
284 281 ~~~~~~~~~~~~~~~
285 *Raw* input cells provide a place in which you can put additional information
286 which you do not want to evaluated by the Notebook. This can be used, for
287 example, to include extra information that is needed when exporting to a
288 certain format. The output after evaluating a raw cell is just a verbatim copy
289 of the input.
282
283 *Raw* input cells provide a place in which you can write *output* directly.
284 Raw cells are not evaluated by the Notebook, and have no output.
285 When passed through nbconvert, Raw cells arrive in the destination format unmodified,
286 allowing you to type full latex into a raw cell, which will only be rendered
287 by latex after conversion by nbconvert.
290 288
291 289 Heading cells
292 290 ~~~~~~~~~~~~~
291
293 292 You can provide a conceptual structure for your computational document as a
294 293 whole using different levels of headings; there are 6 levels available, from
295 294 level 1 (top level) down to level 6 (paragraph). These can be used later for
296 295 constructing tables of contents, etc.
297 296
298 297 As with Markdown cells, a heading input cell is replaced by a rich text
299 298 rendering of the heading when the cell is executed.
300 299
301 300
302 301 Basic workflow
303 302 --------------
303
304 304 The normal workflow in a notebook is, then, quite similar to a standard
305 305 IPython session, with the difference that you can edit cells in-place multiple
306 306 times until you obtain the desired results, rather than having to
307 307 rerun separate scripts with the ``%run`` magic command. (Magic commands do,
308 308 however, also work in the notebook; see below).
309 309
310 310 Typically, you will work on a computational problem in pieces, organizing
311 311 related ideas into cells and moving forward once previous parts work
312 312 correctly. This is much more convenient for interactive exploration than
313 313 breaking up a computation into scripts that must be executed together, as was
314 314 previously necessary, especially if parts of them take a long time to run
315 315
316 316 The only significant limitation that the Notebook currently has, compared to
317 317 the Qt console, is that it cannot run any code that expects input from the
318 318 kernel (such as scripts that call :func:`raw_input`). Very importantly, this
319 319 means that the ``%debug`` magic does *not* currently work in the notebook!
320 320
321 321 This limitation will be overcome in the future, but in the meantime, there is
322 322 a simple solution for debugging: you can attach a Qt console to your existing
323 323 notebook kernel, and run ``%debug`` from the Qt console.
324 324 If your notebook is running on a local computer (i.e. if you are accessing it
325 325 via your localhost address at ``127.0.0.1``), then you can just type
326 326 ``%qtconsole`` in the notebook and a Qt console will open up, connected to
327 327 that same kernel.
328 328
329 329 At certain moments, it may be necessary to interrupt a calculation which is
330 330 taking too long to complete. This may be done with the ``Kernel | Interrupt``
331 331 menu option, or the :kbd:``Ctrl-i`` keyboard shortcut.
332 332 Similarly, it may be necessary or desirable to restart the whole computational
333 333 process, with the ``Kernel | Restart`` menu option or :kbd:``Ctrl-.``
334 334 shortcut. This gives an equivalent state to loading the notebook document
335 335 afresh.
336 336
337 337
338 338 .. warning::
339 339
340 340 While in simple cases you can "roundtrip" a notebook to Python, edit the
341 341 Python file, and then import it back without loss of main content, this is
342 342 in general *not guaranteed to work*. First, there is extra metadata
343 343 saved in the notebook that may not be saved to the ``.py`` format. And as
344 344 the notebook format evolves in complexity, there will be attributes of the
345 345 notebook that will not survive a roundtrip through the Python form. You
346 346 should think of the Python format as a way to output a script version of a
347 347 notebook and the import capabilities as a way to load existing code to get
348 348 a notebook started. But the Python version is *not* an alternate notebook
349 349 format.
350 350
351 351
352 352 Keyboard shortcuts
353 353 ~~~~~~~~~~~~~~~~~~
354 354 All actions in the notebook can be achieved with the mouse, but keyboard
355 355 shortcuts are also available for the most common ones, so that productive use
356 356 of the notebook can be achieved with minimal mouse usage. The main shortcuts
357 357 to remember are the following:
358 358
359 359 * :kbd:`Shift-Enter`:
360 360
361 361 Execute the current cell, show output (if any), and jump to the next cell
362 362 below. If :kbd:`Shift-Enter` is invoked on the last input cell, a new code
363 363 cell will also be created. Note that in the notebook, typing :kbd:`Enter`
364 364 on its own *never* forces execution, but rather just inserts a new line in
365 365 the current input cell. In the Notebook it is thus always necessary to use
366 366 :kbd:`Shift-Enter` to execute the cell (or use the ``Cell | Run`` menu
367 367 item).
368 368
369 369 * :kbd:`Ctrl-Enter`:
370 370 Execute the current cell as if it were in "terminal mode", where any
371 371 output is shown, but the cursor *remains* in the current cell. This is
372 372 convenient for doing quick experiments in place, or for querying things
373 373 like filesystem content, without needing to create additional cells that
374 374 you may not want to be saved in the notebook.
375 375
376 376 * :kbd:`Alt-Enter`:
377 377 Executes the current cell, shows the output, and inserts a *new* input
378 378 cell between the current cell and the adjacent cell (if one exists). This
379 379 is thus a shortcut for the sequence :kbd:`Shift-Enter`, :kbd:`Ctrl-m a`.
380 380 (:kbd:`Ctrl-m a` adds a new cell above the current one.)
381 381
382 382 * :kbd:`Ctrl-m`:
383 383 This is the prefix for *all* other shortcuts, which consist of :kbd:`Ctrl-m`
384 384 followed by a single letter or character. For example, if you type
385 385 :kbd:`Ctrl-m h` (that is, the sole letter :kbd:`h` after :kbd:`Ctrl-m`),
386 386 IPython will show you all the available keyboard shortcuts.
387 387
388 388
389 389 Magic commands
390 390 --------------
391 391 Magic commands, or *magics*, are commands for controlling IPython itself.
392 392 They all begin with ``%`` and are entered into code input cells; the code
393 393 cells are executed as usual with :kbd:`Shift-Enter`.
394 394
395 395 The magic commands call special functions defined by IPython which manipulate
396 396 the computational state in certain ways.
397 397
398 398 There are two types of magics:
399 399
400 400 - **line magics**:
401 401
402 402 These begin with a single ``%`` and take as arguments the rest of the
403 403 *same line* of the code cell. Any other lines of the code cell are
404 404 treated as if they were part of a standard code cell.
405 405
406 406 - **cell magics**:
407 407
408 408 These begin with ``%%`` and operate on the *entire* remaining contents
409 409 of the code cell.
410 410
411 411 Line magics
412 412 ~~~~~~~~~~~
413 413 Some of the available line magics are the following:
414 414
415 415 * ``%load filename``:
416 416
417 417 Loads the contents of the file ``filename`` into a new code cell. This
418 418 can be a URL for a remote file.
419 419
420 420 * ``%timeit code``:
421 421
422 422 An easy way to time how long the single line of code ``code`` takes to
423 423 run
424 424
425 425 * ``%config``:
426 426
427 427 Configuration of the IPython Notebook
428 428
429 429 * ``%lsmagic``:
430 430
431 431 Provides a list of all available magic commands
432 432
433 433 Cell magics
434 434 ~~~~~~~~~~~
435 435
436 436 * ``%%latex``:
437 437
438 438 Renders the entire contents of the cell in LaTeX, without needing to use
439 439 explicit LaTeX delimiters.
440 440
441 441 * ``%%bash``:
442 442
443 443 The code cell is executed by sending it to be executed by ``bash``. The
444 444 output of the ``bash`` commands is captured and displayed in the
445 445 notebook.
446 446
447 447 * ``%%file filename``:
448 448
449 449 Writes the contents of the cell to the file ``filename``.
450 450 **Caution**: The file is over-written without warning!
451 451
452 452 * ``%%R``:
453 453
454 454 Execute the contents of the cell using the R language.
455 455
456 456 * ``%%timeit``:
457 457
458 458 Version of ``%timeit`` which times the entire block of code in the
459 459 current code cell.
460 460
461 461
462 462
463 463 Several of the cell magics provide functionality to manipulate the filesystem
464 464 of a remote server to which you otherwise do not have access.
465 465
466 466
467 467 Plotting
468 468 --------
469 469 One major feature of the Notebook is the ability to interact with
470 470 plots that are the output of running code cells. IPython is designed to work
471 471 seamlessly with the ``matplotlib`` plotting library to provide this
472 472 functionality.
473 473
474 474 To set this up, before any plotting is performed you must execute the
475 475 ``%matplotlib`` magic command. This performs the necessary behind-the-scenes
476 476 setup for IPython to work correctly hand in hand with ``matplotlib``; it does
477 477 *not*, however, actually execute any Python ``import`` commands, that is, no
478 478 names are added to the namespace.
479 479
480 480 For more agile *interactive* use of the notebook space, an alternative magic,
481 481 ``%pylab``, is provided. This does the same work as the ``%matplotlib`` magic,
482 482 but *in addition* it automatically executes a standard sequence of ``import``
483 483 statements required to work with the ``%matplotlib`` library, importing the
484 484 following names into the namespace:
485 485
486 486 ``numpy`` as ``np``; ``matplotlib.pyplot`` as ``plt``;
487 487 ``matplotlib``, ``pylab`` and ``mlab`` from ``matplotlib``; and *all names*
488 488 from within ``numpy`` and ``pylab``.
489 489
490 490 However, the use of ``%pylab`` is discouraged, since names coming from
491 491 different packages may collide. In general, the use of ``from package import
492 492 *`` is discouraged. A better option is then::
493 493
494 494 %pylab --no-import-all
495 495
496 496 which imports the names listed above, but does *not* perform this
497 497 ``import *`` imports.
498 498
499 499 If the ``%matplotlib`` or ``%pylab` magics are called without an argument, the
500 500 output of a plotting command is displayed using the default ``matplotlib``
501 501 backend in a separate window. Alternatively, the backend can be explicitly
502 502 requested using, for example::
503 503
504 504 %matplotlib gtk
505 505
506 506 A particularly interesting backend is the ``inline`` backend.
507 507 This is applicable only for the IPython Notebook and the IPython Qtconsole.
508 508 It can be invoked as follows::
509 509
510 510 %matplotlib inline
511 511
512 512 With this backend, output of plotting commands is displayed *inline* within
513 513 the notebook format, directly below the input cell that produced it. The
514 514 resulting plots will then also be stored in the notebook document. This
515 515 provides a key part of the functionality for reproducibility_ that the IPython
516 516 Notebook provides.
517 517
518 518 .. _reproducibility: https://en.wikipedia.org/wiki/Reproducibility
519 519
520 520
521 521
522 522 Configuring the IPython Notebook
523 523 --------------------------------
524 524 The IPython Notebook can be run with a variety of command line arguments.
525 525 To see a list of available options enter::
526 526
527 527 $ ipython notebook --help
528 528
529 529 Defaults for these options can also be set by creating a file named
530 530 ``ipython_notebook_config.py`` in your IPython *profile folder*. The profile
531 531 folder is a subfolder of your IPython directory; to find out where it is
532 532 located, run::
533 533
534 534 $ ipython locate
535 535
536 536 To create a new set of default configuration files, with lots of information
537 537 on available options, use::
538 538
539 539 $ ipython profile create
540 540
541 541 .. seealso:
542 542
543 543 :ref:`config_overview`, in particular :ref:`Profiles`.
544 544
545 545
546 546 Importing `.py` files
547 547 ----------------------
548 548
549 549
550 550 ``.py`` files will be imported into the IPython Notebook as a notebook with
551 the same basename, but an ``.ipynb`` extension, located in the working
551 the same basename, but an ``.ipynb`` extension, located in the notebook
552 552 directory. The notebook created will have just one cell, which will contain
553 553 all the code in the ``.py`` file. You can later manually partition this into
554 554 individual cells using the ``Edit | Split Cell`` menu option, or the
555 555 :kbd:`Ctrl-m -` keyboard shortcut.
556 556
557 557 .. Alternatively, prior to importing the ``.py``, you can manually add ``# <
558 558 nbformat>2</nbformat>`` at the start of the file, and then add separators for
559 559 text and code cells, to get a cleaner import with the file already broken into
560 560 individual cells.
561 561
562
563
564 .. _Markdown: http://daringfireball.net/projects/markdown/basics
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