python - Python如何仅当值后选择的分隔符是数字时才拆分字符串？

Question

我正在尝试使用 lib re 拆分字符串，并且我需要使用一些分隔符拆分值，但对于一个特定的我遇到了一些麻烦。问题是如果空格后面的下一个字符是数字，我需要拆分。例如

import re
a = 'Trying de one'
b = 'Trying de 10'
a = re.split('ate |de |do ',a)[0]
b = re.split('ate |de |do ',b)[0]

我需要的是输出：

a = 'Trying de one'
b = 'Trying de '

而且我每次都得到第二个。

标签： pythonsplit

Answer 1

You can capture either ate de or do followed by a space that you want to keep, and match 1 or more digits that you want to remove.

In the replacement use capture group 1.

import re

pattern = r"\b(ate |d[eo] )\d+";

a = 'Trying de one'
b = 'Trying de 10'

a = re.sub(pattern, r'\1', a)
b = re.sub(pattern, r'\1', b)

print(a)
print(b)

Regex demo | Python demo

Output

Trying de one
Trying de 

---

If you have to use split, one option is to make use of lookarounds, asserting either ate de or do on the left and a digit on the right.

import re

pattern = r"(?:(?<=ate )|(?<=d[eo] ))(?=\d)"

a = 'Trying de one'
b = 'Trying de 10'

a = re.split(pattern, a)
b = re.split(pattern, b)
print(a[0])
print(b[0])

Output

Trying de one
Trying de 

Regex demo | Python demo