string 在 Scala 中替换字符串中的字符
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Replacing characters in a String in Scala
提问by Hanxue
I am trying to create a method to convert characters within a String, specifically converting all '0' to ' '. This is the code that I am using:
我正在尝试创建一种方法来转换字符串中的字符，特别是将所有 '0' 转换为 ' '。这是我正在使用的代码：
def removeZeros(s: String) = {
val charArray = s.toCharArray
charArray.map( c => if(c == '0') ' ')
new String(charArray)
}
Is there a simpler way to do it? This syntax is not valid:
有没有更简单的方法来做到这一点？此语法无效：
def removeZeros(s: String) =
new String(s.toCharArray.map( c => if(c == '0') ' '))
回答by Lee
You can map strings directly:
您可以直接映射字符串：
def removeZero(s: String) = s.map(c => if(c == '0') ' ' else c)
alternatively you could use replace:
或者你可以使用replace：
s.replace('0', ' ')
回答by Randall Schulz
Very simple:
很简单：
scala> "FooN00b".filterNot(_ == '0')
res0: String = FooNb
To replace some characters with others:
用其他字符替换某些字符：
scala> "FooN00b" map { case '0' => 'o' case 'N' => 'D' case c => c }
res1: String = FooDoob
To replace one character with some arbitrary number of characters:
用任意数量的字符替换一个字符：
scala> "FooN00b" flatMap { case '0' => "oOo" case 'N' => "" case c => s"$c" }
res2: String = FoooOooOob
回答by josh
According to Ignacio Alorre, if you want to replace others chars into string:
根据 Ignacio Alorre 的说法，如果您想将其他字符替换为字符串：
def replaceChars (str: String) = str.map(c => if (c == '0') ' ' else if (c =='T') '_' else if (c=='-') '_' else if(c=='Z') '.' else c)
val charReplaced = replaceChars("N000TZ")
回答by Jitendra Pradhan
/**
how to replace a empty chachter in string
**/
val name="Jeeta"
val afterReplace=name.replace(""+'a',"")
回答by moped
The go-to way to do it is to use s.replace('0', ' ')
这样做的首选方法是使用 s.replace('0', ' ')
Just for training purposes you might use tail-recursion to achieve that as well.
仅出于培训目的，您也可以使用尾递归来实现这一目标。
def replace(s: String): String = {
def go(chars: List[Char], acc: List[Char]): List[Char] = chars match {
case Nil => acc.reverse
case '0' :: xs => go(xs, ' ' :: acc)
case x :: xs => go(xs, x :: acc)
}
go(s.toCharArray.toList, Nil).mkString
}
replace("01230123") // " 123 123"
and more generally:
更普遍的是：
def replace(s: String, find: Char, replacement: Char): String = {
def go(chars: List[Char], acc: List[Char]): List[Char] = chars match {
case Nil => acc.reverse
case `find` :: xs => go(xs, replacement :: acc)
case x :: xs => go(xs, x :: acc)
}
go(s.toCharArray.toList, Nil).mkString
}
replace("01230123", '0', ' ') // " 123 123"
