How can i access a char in string in at specific number? [closed]

问题

I tried this code but it is giving me errors. So how can i access a character in a string in kotlin. in java it can be done by charAt() method.

private fun abc(x: String) {
    var i: Int = 0
    while (x[i].toString() != "+") {
        var y: Char = x[i]
        i++
    }
}

回答1:

The equivalent of Javas String.charAt() in Kotlin is String.get(). Since this is implemented as an operator, you can use [index] instead of get(index). For example

val firstChar: Char = "foo"[0]

or if you prefer

val someString: String = "bar"
val firstChar: Char = someString.get(0)

回答2:

Could you please try this method instead?

private fun abc(x: String) {
    $p = 1; 
    do {
        $p++
    }while (x[p]!= "+")
}

回答3:

The beauty of Kotlin is that you can do it in few ways, eg.

You can simply access it by index:
```
while (x[i] != '+') {
    i++
}
```

Converting to CharArray

val chars: CharArray = x.toCharArray()

while (chars[i] != '+') {
    i++
}

You can also use idiomatic Kotlin (preferred):

forEach

x.forEach { c ->
    if (c == '+') return@forEach
}

forEachIndexed if you care about index

x.forEachIndexed { index, c ->
    if (c == '+') {
        println("index=$index")
        return@forEachIndexed
    }
}

In both cases, your character is accessed with c

来源：https://stackoverflow.com/questions/50297288/how-can-i-access-a-char-in-string-in-at-specific-number

标签

string

kotlin

char

kotlin-android-extensions