Swift中字符串中子字符串的出现次数 [英] Number of occurrences of substring in string in Swift

问题描述

我的主字符串是hello Swift Swift and Swift"，子字符串是Swift.我需要获取子字符串Swift"在提到的字符串中出现的次数.

My main string is "hello Swift Swift and Swift" and substring is Swift. I need to get the number of times the substring "Swift" occurs in the mentioned string.

这段代码可以判断模式是否存在.

This code can determine whether the pattern exists.

var string = "hello Swift Swift and Swift"

if string.rangeOfString("Swift") != nil {
    println("exists")
}

现在我需要知道出现的次数.

Now I need to know the number of occurrence.

推荐答案

一个简单的方法是在 "Swift" 上拆分，然后从零件数中减去 1:

A simple approach would be to split on "Swift", and subtract 1 from the number of parts:

let s = "hello Swift Swift and Swift"
let tok =  s.components(separatedBy:"Swift")
print(tok.count-1)

此代码打印 3.

在 Swift 3 语法之前，代码如下所示:

Before Swift 3 syntax the code looked like this:

let tok =  s.componentsSeparatedByString("Swift")

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