[英]Regex how to search more than one digits in a phrase
I have a dataset with strings that include phrases + temperatures:我有一个包含短语+温度的字符串数据集:
ex.前任。 string = "New York is humid with 15.43C".
string = "纽约潮湿,气温为 15.43C"。 only_temp="15.43C"
only_temp="15.43C"
My code: -->If only_temp="15.43C" then我的代码: -->If only_temp="15.43C" 那么
re.search('\d+.\d\dC', string)
finds it. re.search('\d+.\d\dC', string)
找到它。
-->If "New York is humid with 15.43C" . -->如果“纽约潮湿,气温为 15.43C” 。
re.search("(.*)(\d+.\d\dC)", string)
finds 2 groups that " New York is humid with" and "5.43C" . re.search("(.*)(\d+.\d\dC)", string)
找到“纽约潮湿”和“5.43C”的2组。 ( Instead of 15.43C) (而不是 15.43C)
I believe that the problem is in.* but I cannot find a solution.我相信问题出在。*但我找不到解决方案。
In在
re.search("(.*)(\d+.\d\dC)",string)
the '(.*)'
greedily capturing anything. '(.*)'
贪婪地捕捉任何东西。 The following '(\d+.\d\dC)'
captures greedily as well - but it only enforces 1+ digits before the dot.以下
'(\d+.\d\dC)'
也贪婪地捕获 - 但它只在点之前强制执行 1+ 位。 That is why the first expression captures the 1
.这就是第一个表达式捕获
1
的原因。
Make it non-greedy:让它不贪婪:
re.search("(.*?)(\d+.\d\dC)",string)
so the first expression only captures lazy / he least it has to.所以第一个表达式只捕获lazy / he 至少它必须。 Then the followup will capture the full degrees centigrade.
然后后续将捕获全摄氏度。 You may as well make the first non-capturing if you do not need it at all:
如果您根本不需要它,您也可以进行第一个非捕获:
re.search("(?:.*?)(\d+.\d\dC)",string)
Demo:演示:
import re
string = "New York is humid with 15.43C"
only_temp ="15.43C"
s = re.search("(?:.*?)(\d+.\d\dC)", string)
print(s.groups())
Output: Output:
('15.43C',)
I think you could simply your regex:我认为你可以简单地使用你的正则表达式:
import re
s = 'New York is humid with 15.43C'
re.search("([\d\.]+C$)", s).groups()
OUTPUT OUTPUT
('15.43C',)
While it is true that [\d\.]+
is more free form than \d+.\d\d
- I think it is reasonably safe to assume that a combination of numbers and dots express the temperature.虽然
[\d\.]+
确实比\d+.\d\d
更自由的形式- 我认为假设数字和点的组合表示温度是相当安全的。
For example if your sentence is like:例如,如果你的句子是这样的:
s = 'New York is humid with 16C'
a more restrictive pattern won't return any match.更严格的模式不会返回任何匹配项。
In any case, note that the dot needs to be escaped - given that in regex .
在任何情况下,请注意点需要转义 - 考虑到 regex
.
means any character, otherwise:表示任何字符,否则:
s = "New York is humid with 15A43C"
re.search("(?:.*?)(\d+.\d\dC)", s).groups()
will return a match将返回匹配
OUTPUT OUTPUT
('15A43C',)
I do understand that it is rationaly and reasonably safe to assume that \d+.\d\dC
will generally match a Celsius temperature - I am just saying that you are not matching a dot, if that is the intention.我确实理解假设
\d+.\d\dC
通常会匹配摄氏温度是合理且合理的安全 - 我只是说你不匹配一个点,如果这是意图的话。
There were several mistakes in your regex:您的正则表达式中有几个错误:
.
will match any character, not a period , use \.
\.
to match the decimal separators = 'New York is humid with 15.43C'
m = re.search('(.*?)\s*(\d+\.\d{,2}C)', s)
m.groups()
# ('New York is humid with', '15.43C')
If you want to handle the case where there is no decimal part:如果要处理没有小数部分的情况:
s = 'New York is humid with 15C'
m = re.search('(.*?)\s*(\d+(?:\.\d{,2})?C)', s)
m.groups()
# ('New York is humid with', '15C')
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