如何在Swift中找出字母是字母数字还是数字

如何在Swift中找出字母是字母数字还是数字

本文介绍了如何在Swift中找出字母是字母数字还是数字的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!

问题描述

我要计算以下字符串中的字母,数字和特殊字符的数量:

I want to count the number of letters, digits and special characters in the following string:

let phrase = "The final score was 32-31!"

我尝试过:

for tempChar in phrase {
    if (tempChar >= "a" && tempChar <= "z") {
       letterCounter++
    }
// etc.

但是我遇到了错误。我对此尝试了各种其他变化-仍然出现错误-例如:

but I'm getting errors. I tried all sorts of other variations on this - still getting error - such as:


推荐答案

Swift 3的更新

let letters = CharacterSet.letters
let digits = CharacterSet.decimalDigits

var letterCount = 0
var digitCount = 0

for uni in phrase.unicodeScalars {
    if letters.contains(uni) {
        letterCount += 1
    } else if digits.contains(uni) {
        digitCount += 1
    }
}






(以前的Swift版本的答案)

可能的Swift解决方案:

A possible Swift solution:

var letterCounter = 0
var digitCount = 0
let phrase = "The final score was 32-31!"
for tempChar in phrase.unicodeScalars {
    if tempChar.isAlpha() {
        letterCounter++
    } else if tempChar.isDigit() {
        digitCount++
    }
}






更新: 上述解决方案仅适用于ASCII字符集中的字符
,即不能将Ä,é或ø识别为字母。以下替代
解决方案使用Foundation框架中的 NSCharacterSet ,它可以根据字符Unicode字符类测试字符


Update: The above solution works only with characters in the ASCII character set,i.e. it does not recognize Ä, é or ø as letters. The following alternativesolution uses NSCharacterSet from the Foundation framework, which can test charactersbased on their Unicode character classes:

let letters = NSCharacterSet.letterCharacterSet()
let digits = NSCharacterSet.decimalDigitCharacterSet()

var letterCount = 0
var digitCount = 0

for uni in phrase.unicodeScalars {
    if letters.longCharacterIsMember(uni.value) {
        letterCount++
    } else if digits.longCharacterIsMember(uni.value) {
        digitCount++
    }
}






更新2:从Xcode 6 beta 4开始,第一个解决方案不再起作用,因为
isAlpha ()和相关(仅ASCII)方法已从Swift中删除。
第二个解决方案仍然有效。


Update 2: As of Xcode 6 beta 4, the first solution does not work anymore, becausethe isAlpha() and related (ASCII-only) methods have been removed from Swift.The second solution still works.

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08-31 03:54