[Python-Dev] performance of {} versus dict()

[Xavier Morel]

On 2012-11-14, at 17:42 , Richard Oudkerk wrote:

> On 14/11/2012 4:23pm, Serhiy Storchaka wrote:
>> PEP 8 recommends:
>> 
>> a_dict = dict(
>>     x=1,
>>     y=2,
>>     z=3,
>>     ...
>> )
>> 
>> and
>> 
>> a_dict = {
>>     'x': 1,
>>     'y': 2,
>>     'z': 3,
>>     ...
>> }
> 
> In which section?  I can't see such a recommendation.

Whitespace in Expressions and Statements > Other Recommendations

3rd bullet:

—
Don't use spaces around the = sign when used to indicate a keyword argument or a default parameter value.

Yes:

def complex(real, imag=0.0):
    return magic(r=real, i=imag)

No:

def complex(real, imag = 0.0):
    return magic(r = real, i = imag)
—