Why doesn't IPython timeit work with literal set?
IPython timeit
sometimes breaks when using a set of literals:
In [1]: timeit 'potato' in {'spam', 'eggs', 'potato'}
10000000 loops, best of 3: 27.6 ns per loop
In [2]: timeit 'potato' in {'potato'}
---------------------------------------------------------------------------
NameError Traceback (most recent call last)
<ipython-input-2-9f61653b85de> in <module>()
----> 1 get_ipython().magic(u"timeit 'potato' in {'potato'}")
/usr/local/lib/python2.7/dist-packages/IPython/core/interactiveshell.pyc in magic(self, arg_s)
2203 magic_name, _, magic_arg_s = arg_s.partition(' ')
2204 magic_name = magic_name.lstrip(prefilter.ESC_MAGIC)
-> 2205 return self.run_line_magic(magic_name, magic_arg_s)
2206
2207 #-------------------------------------------------------------------------
/usr/local/lib/python2.7/dist-packages/IPython/core/interactiveshell.pyc in run_line_magic(self, magic_name, line)
2124 kwargs['local_ns'] = sys._getframe(stack_depth).f_locals
2125 with self.builtin_trap:
-> 2126 result = fn(*args,**kwargs)
2127 return result
2128
/usr/local/lib/python2.7/dist-packages/IPython/core/magics/execution.pyc in timeit(self, line, cell)
/usr/local/lib/python2.7/dist-packages/IPython/core/magic.pyc in <lambda>(f, *a, **k)
191 # but it overkill for just that one bit of state.
192 def magic_deco(arg):
--> 193 call = lambda f, *a, **k: f(*a, **k)
194
195 if callable(arg):
/usr/local/lib/python2.7/dist-packages/IPython/core/magics/execution.pyc in timeit(self, line, cell)
1011 number = 1
1012 for _ in range(1, 10):
-> 1013 if timer.timeit(number) >= 0.2:
1014 break
1015 number *= 10
/usr/lib/python2.7/timeit.pyc in timeit(self, number)
193 gc.disable()
194 try:
--> 195 timing = self.inner(it, self.timer)
196 finally:
197 if gcold:
<magic-timeit> in inner(_it, _timer)
NameError: global name 'potato' is not defined
IPython v2.2.0, does not work on both python 2.x and python3.
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1 answer
This is a bug in IPython caused by the syntax for expanding {var} references in ipython magic, contrary to the same syntax chosen by the python developers for the literal set.
If you run into this problem, perhaps a workaround is to exit the set of literals with double curly braces:
In [1]: timeit 0 in {0}
# TypeError: argument of type 'int' is not iterable
In [2]: timeit 0 in {{0}}
10000000 loops, best of 3: 60.1 ns per loop
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