Capturing Output with %%capture¶
One of IPython's new cell magics is %%capture
, which captures stdout/err for a cell,
and discards them or stores them in variables in your namespace.
import sys
By default, it just swallows it up. This is a simple way to suppress unwanted output.
%%capture
print 'hi, stdout'
print >> sys.stderr, 'hi, stderr'
If you specify -o
or -e
, then stdout and/or stderr will be stored in those variables in your namespace.
%%capture -o my_stdout
print 'hi, stdout'
print >> sys.stderr, 'hi, stderr'
my_stdout
%%capture -o my_stdout2 -e my_stderr
print 'hi again, stdout'
print >> sys.stderr, 'hi there, stderr'
sys.stdout.write(my_stdout2)
sys.stderr.write(my_stderr)
%%capture
only captures stdout/err, not displaypub, so you can still do plots and use the display protocol inside %%capture
%pylab inline
%%capture -o wontshutup
print "setting up X"
x = np.linspace(0,5,1000)
print "step 2: constructing y-data"
y = np.sin(x)
print "step 3: display info about y"
plt.plot(x,y)
print "okay, I'm done now"
print wontshutup