diff --git a/Lib/tokenize.py b/Lib/tokenize.py
index 22f28c44269..76ea7a2ef99 100644
--- a/Lib/tokenize.py
+++ b/Lib/tokenize.py
@@ -110,6 +110,21 @@ endprogs = {"'": re.compile(Single), '"': re.compile(Double),
             "UR'''": single3prog, 'UR"""': double3prog,
             'r': None, 'R': None, 'u': None, 'U': None}
 
+triple_quoted = {}
+for t in ("'''", '"""',
+          "r'''", 'r"""', "R'''", 'R"""',
+          "u'''", 'u"""', "U'''", 'U"""',
+          "ur'''", 'ur"""', "Ur'''", 'Ur"""',
+          "uR'''", 'uR"""', "UR'''", 'UR"""'):
+    triple_quoted[t] = t
+single_quoted = {}
+for t in ("'", '"',
+          "r'", 'r"', "R'", 'R"',
+          "u'", 'u"', "U'", 'U"',
+          "ur'", 'ur"', "Ur'", 'Ur"',
+          "uR'", 'uR"', "UR'", 'UR"' ):
+    single_quoted[t] = t
+
 tabsize = 8
 
 class TokenError(Exception): pass
@@ -232,11 +247,7 @@ def generate_tokens(readline):
                                token, spos, epos, line)
                 elif initial == '#':
                     yield (COMMENT, token, spos, epos, line)
-                elif token in ("'''", '"""',               # triple-quoted
-                               "r'''", 'r"""', "R'''", 'R"""',
-                               "u'''", 'u"""', "U'''", 'U"""',
-                               "ur'''", 'ur"""', "Ur'''", 'Ur"""',
-                               "uR'''", 'uR"""', "UR'''", 'UR"""'):
+                elif token in triple_quoted:
                     endprog = endprogs[token]
                     endmatch = endprog.match(line, pos)
                     if endmatch:                           # all on one line
@@ -248,11 +259,9 @@ def generate_tokens(readline):
                         contstr = line[start:]
                         contline = line
                         break
-                elif initial in ("'", '"') or \
-                    token[:2] in ("r'", 'r"', "R'", 'R"',
-                                  "u'", 'u"', "U'", 'U"') or \
-                    token[:3] in ("ur'", 'ur"', "Ur'", 'Ur"',
-                                  "uR'", 'uR"', "UR'", 'UR"' ):
+                elif initial in single_quoted or \
+                    token[:2] in single_quoted or \
+                    token[:3] in single_quoted:
                     if token[-1] == '\n':                  # continued string
                         strstart = (lnum, start)
                         endprog = (endprogs[initial] or endprogs[token[1]] or