Kotlin 删除所有非字母数字字符

Question

我正在尝试从字符串中删除所有非字母数字字符。

我尝试将 replace() 与正则表达式一起使用，如下所示:

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

D/debug: Test. ,replace

D/debug: test. ,replace

为什么标点符号仍然存在？如何只获取字母数字字符？

Answer 1

你需要创建一个正则表达式对象

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