问题
Possible Duplicate:
Line continuation for list comprehensions or generator expressions in python
What is the the most pythonic way to write a long list comprehension? This list comprehension comes out to 145 columns:
memberdef_list = [elem for elem in from_cache(classname, 'memberdefs') if elem.argsstring != '[]' and 'std::string' in null2string(elem.vartype)]
How should it look if I break it into multiple lines? I couldn't find anything about this in the Python style guides.
回答1:
PEP 8 kinda predates list comprehensions. I usually break these up over multiple lines at logical locations:
memberdef_list = [elem for elem in from_cache(classname, 'memberdefs')
if elem.argsstring != '[]' and
'std::string' in null2string(elem.vartype)]
Mostly though, I'd forgo the involved test there in the first place:
def stdstring_args(elem):
if elem.argstring == '[]':
return False
return 'std::string' in null2string(elem.vartype)
memberdef_list = [elem for elem in from_cache(classname, 'memberdefs')
if stdstring_args(elem)]
来源：https://stackoverflow.com/questions/12372186/pythonic-style-for-multiline-list-comprehension