如何使用python替换字符串中的多个字符? [英] How can I replace multiple characters in a string using python?

问题描述

我在弄清楚如何替换字符串中的多个字符时遇到了一些麻烦.我正在尝试编写一个名为 replace(string) 的函数，它接受一个输入，并用另一个字母替换输入中的某些字母.

假设我有字符串WXYZ"，我想用 Y 替换所有 W，用 Z 替换 X，用 W 替换 Y，用 X 替换 Z.无论输入是什么，我都希望它进行替换.因此，如果我也执行诸如 replace("WWZXXWWXYYZWYYY") 之类的操作，它应该像我上面所说的那样替换字母.

这是我到目前为止所做的:

def 替换(字符串):对于字符串中的字母:string = string.replace("W","Y").replace("X","Z").replace("Y","W").replace("Z","X")打印(字符串)

但是当我用 replace("WXYZ") 运行它时

我得到的代码输出为:WXWX

而不是将 YZWX 作为输出.我也想使用 python 的内置函数.谁能帮我解决一下，谢谢！

解决方案

请注意，您的调用的结构是将 W 替换为 Y 在第一个调用，然后在第三次调用中再次将 Y 替换为 W，撤消第一次调用的输出.

您应该使用 str.translate，它比一堆链接的 replace 调用更高效和健壮:

_tab = str.maketrans(dict(zip('WXYZ', 'YZWX')))定义替换(字符串):返回 string.translate(_tab)

<小时><预><代码>>>>替换('WXYZ')'YZWX'>>>替换(WWZYWXXWYYZW")'YYXWYZZYWWXY'

I am having some trouble figuring out how to replace multiple characters in a string.I am trying to write a functions called replace(string) that takes in an input, and replaces certain letters in the input with another letter.

Lets say I have the string "WXYZ" and I want to replace all the W with Y, X with Z, Y with W, and Z with X. I want it to do the replacement no matter what the input is. so if I also do something like replace("WWZXWWXYYZWYYY") it should replace the letters like I said above.

This is what I have done so far:

def replace(string):
for letters in string:
    string = string.replace("W","Y").replace("X","Z").replace("Y","W").replace("Z","X")
print(string)

but when I run it with replace("WXYZ")

I get the output of the code as: WXWX

Instead of getting YZWX as the output. I also want to use the built in functions of python as well. Can someone help me figure this out, thank you!

解决方案

Note that your calls are structured in such a way that W is replaced with Y in the first call, and then Y is again replaced with W in the third call, undoing the first call's output.

You should be using str.translate, it's much more efficient and robust than a bunch of chained replace calls:

_tab = str.maketrans(dict(zip('WXYZ', 'YZWX')))
def replace(string):
    return string.translate(_tab)

---

>>> replace('WXYZ')
'YZWX'
>>> replace("WWZYWXXWYYZW")
'YYXWYZZYWWXY'

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