diff --git a/hgext/hgk.py b/hgext/hgk.py
--- a/hgext/hgk.py
+++ b/hgext/hgk.py
@@ -221,18 +221,17 @@ def revtree(ui, args, repo, full="tree",
 
     # figure out which commits they are asking for and which ones they
     # want us to stop on
-    for i in xrange(len(args)):
-        if args[i].startswith('^'):
-            s = repo.lookup(args[i][1:])
+    for i, arg in enumerate(args):
+        if arg.startswith('^'):
+            s = repo.lookup(arg[1:])
             stop_sha1.append(s)
             want_sha1.append(s)
-        elif args[i] != 'HEAD':
-            want_sha1.append(repo.lookup(args[i]))
+        elif arg != 'HEAD':
+            want_sha1.append(repo.lookup(arg))
 
     # calculate the graph for the supplied commits
-    for i in xrange(len(want_sha1)):
+    for i, n in enumerate(want_sha1):
         reachable.append(set());
-        n = want_sha1[i];
         visit = [n];
         reachable[i].add(n)
         while visit:
diff --git a/hgext/mq.py b/hgext/mq.py
--- a/hgext/mq.py
+++ b/hgext/mq.py
@@ -112,8 +112,8 @@ class patchheader(object):
                     self.message = self.message[2:]
                     break
         ci = 0
-        for mi in xrange(len(self.message)):
-            while self.message[mi] != self.comments[ci]:
+        for mi in self.message:
+            while mi != self.comments[ci]:
                 ci += 1
             del self.comments[ci]
 
@@ -827,8 +827,7 @@ class queue:
 
     def isapplied(self, patch):
         """returns (index, rev, patch)"""
-        for i in xrange(len(self.applied)):
-            a = self.applied[i]
+        for i, a in enumerate(self.applied):
             if a.name == patch:
                 return (i, a.rev, a.name)
         return None
@@ -1407,15 +1406,15 @@ class queue:
         series = []
         applied = []
         qpp = None
-        for i in xrange(len(lines)):
-            if lines[i] == 'Patch Data:':
+        for i, line in enumerate(lines):
+            if line == 'Patch Data:':
                 datastart = i + 1
-            elif lines[i].startswith('Dirstate:'):
-                l = lines[i].rstrip()
+            elif line.startswith('Dirstate:'):
+                l = line.rstrip()
                 l = l[10:].split(' ')
                 qpp = [ bin(x) for x in l ]
             elif datastart != None:
-                l = lines[i].rstrip()
+                l = line.rstrip()
                 se = statusentry(l)
                 file_ = se.name
                 if se.rev:
diff --git a/mercurial/mdiff.py b/mercurial/mdiff.py
--- a/mercurial/mdiff.py
+++ b/mercurial/mdiff.py
@@ -185,7 +185,7 @@ def bunidiff(t1, t2, l1, l2, header1, he
     #
     diff = bdiff.blocks(t1, t2)
     hunk = None
-    for i in xrange(len(diff)):
+    for i, s1 in enumerate(diff):
         # The first match is special.
         # we've either found a match starting at line 0 or a match later
         # in the file.  If it starts later, old and new below will both be
@@ -195,7 +195,6 @@ def bunidiff(t1, t2, l1, l2, header1, he
         else:
             s = [0, 0, 0, 0]
         delta = []
-        s1 = diff[i]
         a1 = s[1]
         a2 = s1[0]
         b1 = s[3]
diff --git a/mercurial/patch.py b/mercurial/patch.py
--- a/mercurial/patch.py
+++ b/mercurial/patch.py
@@ -307,8 +307,7 @@ class patchfile:
 
     def hashlines(self):
         self.hash = {}
-        for x in xrange(len(self.lines)):
-            s = self.lines[x]
+        for x, s in enumerate(self.lines):
             self.hash.setdefault(s, []).append(x)
 
     def write_rej(self):
diff --git a/mercurial/pure/base85.py b/mercurial/pure/base85.py
--- a/mercurial/pure/base85.py
+++ b/mercurial/pure/base85.py
@@ -13,8 +13,8 @@ import struct
 _b85dec = {}
 
 def _mkb85dec():
-    for i in range(len(_b85chars)):
-        _b85dec[_b85chars[i]] = i
+    for i, c in enumerate(_b85chars):
+        _b85dec[c] = i
 
 def b85encode(text, pad=False):
     """encode text in base85 format"""
@@ -50,9 +50,9 @@ def b85decode(text):
     for i in range(0, len(text), 5):
         chunk = text[i:i+5]
         acc = 0
-        for j in range(len(chunk)):
+        for j, c in enumerate(chunk):
             try:
-                acc = acc * 85 + _b85dec[chunk[j]]
+                acc = acc * 85 + _b85dec[c]
             except KeyError:
                 raise TypeError('Bad base85 character at byte %d' % (i + j))
         if acc > 4294967295: