获取字符串的长度 [英] Get the length of a String

问题描述

如何获得String 的长度?例如，我定义了一个变量，如:

How do you get the length of a String? For example, I have a variable defined like:

var test1: String = "Scott"

但是，我似乎无法在字符串上找到长度方法.

However, I can't seem to find a length method on the string.

推荐答案

自 Swift 4+ 起

就是:

test1.count

出于原因.

(感谢 Martin R)

(Thanks to Martin R)

从 Swift 2 开始:

在 Swift 2 中，Apple 已将全局函数更改为协议扩展，即与符合协议的任何类型匹配的扩展.因此新的语法是:

With Swift 2, Apple has changed global functions to protocol extensions, extensions that match any type conforming to a protocol. Thus the new syntax is:

test1.characters.count

(感谢 JohnDifoo 的提醒)

(Thanks to JohnDifool for the heads up)

从 Swift 1 开始

使用计数字符方法:

let unusualMenagerie = "Koala 🐨, Snail 🐌, Penguin 🐧, Dromedary 🐪"
println("unusualMenagerie has \(count(unusualMenagerie)) characters")
// prints "unusualMenagerie has 40 characters"

直接来自 Apple Swift 指南

right from the Apple Swift Guide

(注意，对于 Swift 1.2 之前的版本，这将是 countElements(unusualMenagerie))

(note, for versions of Swift earlier than 1.2, this would be countElements(unusualMenagerie) instead)

对于你的变量，它会是

length = count(test1) // was countElements in earlier versions of Swift

或者你可以使用 test1.utf16count

Or you can use test1.utf16count

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