Python “x for x in”语法是什么意思？
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What does the "x for x in" syntax mean?
提问by Martin Melichar
What actually happens when this code is executed:
执行此代码时实际发生的情况：
text = "word1anotherword23nextone456lastone333"
numbers = [x for x in text if x.isdigit()]
print(numbers)
I understand, that []makes a list, .isdigit()checks for True or False if an element of string (text) is a number. However I am unsure about other steps, especially: what does that "x" do in front of for loop?
我知道，如果字符串（文本）的元素是数字，[]则生成一个列表，.isdigit()检查 True 或 False。但是我不确定其他步骤，尤其是：“x”在 for 循环前做了什么？
I know what the output is (below), but how is it done?
我知道输出是什么（如下），但它是如何完成的？
Output: ['1', '2', '3', '4', '5', '6', '3', '3', '3']
采纳答案by ninesalt
This is just standard Python list comprehension. It's a different way of writing a longer for loop. You're looping over all the characters in your string and putting them in the list if the character is a digit.
这只是标准的 Python 列表理解。这是编写更长的 for 循环的另一种方式。如果字符是数字，您将遍历字符串中的所有字符并将它们放入列表中。
See thisfor more info on list comprehension.
有关列表理解的更多信息，请参阅此内容。
