Kotlin删除所有非字母数字字符 [英] Kotlin Remove all non alphanumeric characters

问题描述

我正在尝试从字符串中删除所有非字母数字字符.

I am trying to remove all non alphanumeric characters from a string.

我尝试将replace()与正则表达式一起使用，如下所示:

I tried using replace() with a regex as followed:

var answer = answerEditText.text.toString()
Log.d("debug", answer)
answer = answer.replace("[^A-Za-z0-9 ]", "").toLowerCase()
Log.d("debug", answer)

D/调试:测试. ，替换

D/debug: Test. ,replace

D/调试:测试. ，替换

D/debug: test. ,replace

为什么标点符号仍然存在?如何仅获取字母数字字符?

Why are the punctuation characters still present? How to get only the alphanumeric characters?

推荐答案

您需要创建一个正则表达式对象

You need to create a regex object

var answer = "Test. ,replace"
println(answer)
answer = answer.replace("[^A-Za-z0-9 ]", "") // doesn't work
println(answer)
val re = Regex("[^A-Za-z0-9 ]")
answer = re.replace(answer, "") // works
println(answer)

在线试用: https://try.kotlinlang.org/#/UserProjects/ttqm0r6lisi743f2dltveid1u9/2olerk6jvb10l03q6bkk1lapjn

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