了解Python List Comprehension等效项 [英] Understanding Python List Comprehension equivalent

问题描述

我有以下代码:

listOfStrings = ['i_am_exercising', 'python_functional', 'lists_comprehension']
[ "".join([elem.title() for elem in splited]) for splited in [el.split("_")for el in listOfStrings]]

其结果是:

['IAmExercising', 'PythonFunctional', 'ListsComprehension']

阅读文档，我得到了等效的扩展版本，这会将第一个表达式放在要附加的变量中，将第二个表达式放在要使用for语句进行迭代的列表中:

reading the documentation, i got the equivalent extended version, which puts the first expression in a variable to be appended and the second expression in a list to be iterated with the for statement:

returned = []
for splited in [el.split("_")for el in listOfStrings]: 
            returned.append("".join([elem.title() for elem in splited]))

但是如果我想编写没有任何列表理解的相同代码，最好的方法是怎么做?我尝试了以下代码，效果很好:

but if i want write the same code without any list comprehension, how is the best way to do this? i tried with the following code, which works well:

returned = []
temp = []

for el in listOfStrings:                 
    temp = []                          
    for splited in el.split("_"):       
        temp.append(splited.title())  
    returned.append("".join(temp))

但是我不完全了解如何执行此操作(将列表理解转换为等效的完整扩展格式)

but i didn't completely understood how to do this (transform the list comprehension to an equivalent full extended form)

推荐答案

您可以轻松地从外向内转换:

You can easily convert from outwards to inwards:

listOfStrings = ['i_am_exercising', 'python_functional', 'lists_comprehension']

result = [ "".join([elem.title() for elem in split]) for split in [el.split("_")for el in listOfStrings]]
print result

result = []
for split in [el.split("_") for el in listOfStrings]:
    result.append("".join([elem.title() for elem in split]))
print result

result = []
temp1 = []
for el in listOfStrings:
    temp1.append(el.split("_"))
for split in temp1:
    result.append("".join([elem.title() for elem in split]))
print result

result = []
temp1 = []
for el in listOfStrings:
    temp1.append(el.split("_"))
for split in temp1:
    temp2 = []
    for elem in split:
        temp2.append(elem.title())
    result.append("".join(temp2))
print result

基本上，您只需要遵循以下方案:

Basically you just follow the following scheme:

result = [foo for bar in baz]

变成

result = []
for bar in baz:
    result.append(foo)

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