Python:剥离除数字以外的所有内容 [英] Python: Strip Everything but Numbers

问题描述

我必须从几个字符串中的每一个中提取一个数字(一个测量的时间值).我怎么能优雅地做到这一点?所有数字都是正数，最多有两位小数.(例如:2.3/40.09/101.4 - E 表示法中没有数字).我正在寻找的代码应该做如下伪代码:

<预><代码>>>>花了 2.3 秒".strip(除了.1234567890"之外的所有内容)2.3

解决方案

用正则表达式为数字选择而不是剥离:

导入重新数字 = re.compile(r'\d+(?:\.\d+)?')numbers.findall("花了 2.3 秒")

演示:

<预><代码>>>>进口重新>>>数字 = re.compile(r'\d+(?:\.\d+)?')>>>numbers.findall("花了 2.3 秒")['2.3']

这将返回所有匹配项的列表；这也可以让您在字符串中找到多个数字:

<预><代码>>>>numbers.findall("花了 2.3 到 42.31 秒")['2.3', '42.31']

I have to extract a number (a measured time value) from each of several strings. How could I do this elegantly? All numbers are positive and have a maximum of two decimal places. (E.g.: 2.3/ 40.09/ 101.4 - no numbers in E notation). The code I am looking for should do something like the following pseudocode:

>>> "It took 2.3 seconds".strip(everything but ".1234567890")
2.3

解决方案

Instead of strip, select for the numbers with a regular expression:

import re

numbers = re.compile(r'\d+(?:\.\d+)?')
numbers.findall("It took 2.3 seconds")

Demo:

>>> import re
>>> numbers = re.compile(r'\d+(?:\.\d+)?')
>>> numbers.findall("It took 2.3 seconds")
['2.3']

This returns a list of all matches; this lets you find multiple numbers in a string too:

>>> numbers.findall("It took between 2.3 and 42.31 seconds")
['2.3', '42.31']

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