Question

String replacement in Python并不难，但我想做一些特别的事情：

teststr = 'test test test test'
animals = ['bird','monkey','dog','fox']
#replace 'test' with random item from animals
finalstr = ['dog fox dog monkey']

我写了一个效率很低的版本：

from random import choice
import string
import re

teststr = 'test test test test'
animals = ['bird','monkey','dog','fox']

indexes = [m.start() for m in re.finditer('test', 'test test test test')]
#indexes = [0, 5, 10, 15]
for i in indexes:
    string.replace(teststr, 'test', choice(animals), 1)

#Final result is four random animals
#maybe ['dog fox dog monkey']

它有效，但我相信有一些简单的REGULAR EXPRESSION方法，我不熟悉。

Answer 1

使用re.sub callback：

import re
import random

animals = ['bird','monkey','dog','fox']

def callback(matchobj):
    return random.choice(animals)

teststr = 'test test test test'
ret = re.sub(r'test', callback, teststr)
print(ret)

收益率（例如）

bird bird dog monkey

re.sub的第二个参数可以是字符串或函数（即回调）。如果它是一个函数，则会对正则表达式模式的每个非重叠事件进行调用，并替换其返回值来代替匹配的字符串。

Answer 2

您可以使用re.sub：

>>> from random import choice
>>> import re
>>> teststr = 'test test test test'
>>> animals = ['bird','monkey','dog','fox']
>>> re.sub('test', lambda m: choice(animals), teststr)
'fox monkey bird dog'
>>> re.sub('test', lambda m: choice(animals), teststr)
'fox dog dog bird'
>>> re.sub('test', lambda m: choice(animals), teststr)
'monkey bird monkey monkey'

Answer 3

这可以胜任：

import random, re
def rand_replacement(string, to_be_replaced, items):
    return re.sub(to_be_replaced, lambda x: random.choice(items), string )

用随机项替换Python字符串

3 个答案: