datetime strptime-设置格式以忽略字符串的结尾部分 [英] datetime strptime - set format to ignore trailing part of string

问题描述

我有一个长度可变的字符串，并且我想给strptime一种格式，以便忽略字符串的其余部分.让我举例说明.我有类似的东西

I have a string with variable length and I want to give a format to strptime in order for the rest of the string to be ignored. Let me exemplify. I have something like

9/4/2013,00:00:00,7.8,7.4,9.53
10/4/2013,00:00:00,8.64,7.4,9.53

，我想要一种使命令strptime(line,format)能够读取这些行的格式.类似format='%d/%m/%Y,%H:%M:%S*'的东西，尽管我知道这不起作用.我想我的问题有点类似于这个问题，但是那里没有答案可以帮助我，我的问题会更糟，因为我的琴弦的全长可能会有所不同.我感觉dateutil可以解决我的问题，但是我找不到能解决问题的东西.

and I want a format that makes the command strptime(line,format) work to read those lines. Something like format='%d/%m/%Y,%H:%M:%S*', although I know that doesn't work. I guess my question is kind of similar to this one, but no answer there could help me and my problem is a little worse because the full length of my string can vary. I have a feeling that dateutil could solve my problem, but I can't find something there that does the trick.

我可能可以做类似strptime(''.join(line.split(',')[:2]),format)的操作，但是我不想在与用户相关的问题上诉诸于此.

I can probably do something like strptime(''.join(line.split(',')[:2]),format), but I wouldn't want to resort to that for user-related issues.

推荐答案

您不能让datetime.strptime()忽略部分输入.您的 only 选项实际上是先分割掉多余的文本.

You cannot have datetime.strptime() ignore part of the input.; your only option really is to split off the extra text first.

是的，您要做必须拆分并重新加入您的字符串:

So yes, you do have to split and rejoin your string:

format = '%d/%m/%Y,%H:%M:%S'
datetime.strptime(','.join(line.split(',', 2)[:2]), format)

或找到其他方法来提取信息.您可以使用正则表达式，例如:

or find some other means to extract the information. You could use a regular expression, for example:

datetime_pattern = re.compile(r'(\d{1,2}/\d{1,2}/\d{4},\d{2}:\d{2}:\d{2})')
format = '%d/%m/%Y,%H:%M:%S'
datetime.strptime(datetime_pattern.search(line).group(), format)

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