多行列表理解的Pythonic样式 [英] Pythonic Style for Multiline List Comprehension

问题描述

可能重复：

在python中列表推导或生成器表达式的行继续

最长的列表解释是什么是最python的方式？这个列表解析出现了145列：

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)]

如果我把它分成多行，应该怎么样？我在Python风格指南中找不到任何内容。

How should it look if I break it into multiple lines? I couldn't find anything about this in the Python style guides.

推荐答案

PEP 8有点早于列表推导。我通常在逻辑位置将它们分成多行：

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)]

大部分情况下，我首先放弃参与的测试：

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)]

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