python - 如何在不使用python替换方法的情况下替换句子中的单词

Question

我已经编写了一个函数来替换句子中的单词，而不使用Python内置的替换方法，问题是我的代码在边缘情况下失败，如果该单词与另一个单词组合，我应该将每个出现的 Maybe 替换为也许。看看我的代码

def replace_all (target,find,replace):
                split_target = target.split()
                result = ''
                for i in split_target:
                        if i == find:
                                i = replace
                        result += i + ' '
                return result.strip()
            target = "Maybe she's born with it. Maybe it's Maybeline."
            find = "Maybe"
            replace = "Perhaps"
            print replace_all(target, find, replace)

输出是:

Perhaps she's born with it. Perhaps it's Maybeline.

但我期待它打印这个:

Perhaps she's born with it. Perhaps it's perhapsline. 

请注意最后一个单词 Maybeline 应该更改为 Maybeline。我已经为此奋斗了一个星期了，任何帮助将不胜感激。

Answer 1

原因是您在空格上进行了分割，因此当您比较 i 时至find ，您正在比较 Maybeline.至Maybe 。这不会匹配，因此您不会替换该匹配项。

如果您按要查找的值拆分，然后将各个部分与替换字符串连接起来，您将获得许多字符串，在 Maybe 处进行拆分曾经是，您可以使用 replace 加入这些它们之间的字符串:

def replace_all (target,find,replace):
  return replace.join(target.split(find))

target = "Maybe she's born with it. Maybe it's Maybeline."
find = "Maybe"
replace = "Perhaps"

print(replace_all(target, find, replace))

> Perhaps she's born with it. Perhaps it's Perhapsline.