swift - swift 中的正则表达式

Question

我对 NSRegularExpression 在 swift 中有点困惑，有人可以帮助我吗？

task:1 given ("name","john","name of john")
然后我应该得到["name","john","name of john"]。在这里我应该避免括号。

task:2 given ("name","john","name of john")
然后我应该得到["name","john","name of john"]。在这里我应该避免括号和额外的空格，最后得到一个字符串数组。

task:3 给定 key = value//comment
然后我应该得到["key","value","comment"]。在这里，我应该通过避免 = 和 // 来只获取行中的字符串
我已经为任务 1 尝试了以下代码，但没有通过。

let string = "(name,john,string for user name)"
let pattern = "(?:\\w.*)"

do {
    let regex = try NSRegularExpression(pattern: pattern, options: .caseInsensitive)
    let matches = regex.matches(in: string, options: [], range: NSRange(location: 0, length: string.utf16.count))
    for match in matches {
        if let range = Range(match.range, in: string) {
            let name = string[range]
            print(name)
        }
    }
} catch {
    print("Regex was bad!")
}

提前致谢。

Answer 1

Swift 中的正则表达式

这些帖子可能会帮助您探索 swift 中的正则表达式:

• Does a string match a pattern?
• Swift extract regex matches
• How can I use String slicing subscripts in Swift 4?
• How to use regex with Swift?
• Swift 3 - How do I extract captured groups in regular expressions?
• How to group search regular expressions using swift?

任务 1 和 2

此表达式可能会帮助您匹配任务 1 和任务 2 所需的输出:

"(\s+)?([a-z\s]+?)(\s+)?"

---

基于 Rob的建议，您可以大大减少边界，例如字符列表 [a-z\s]。例如这里，我们还可以使用:

"(\s+)?(.*?)(\s+)?"

或

"(\s+)?(.+?)(\s+)?"

简单地传递两个 " 和/或 space 之间的所有内容。

正则表达式

如果这不是您想要的表达式，您可以在 regex101.com 中修改/更改您的表达式.

正则表达式电路

您还可以在 jex.im 中可视化您的表情:

JavaScript 演示

const regex = /"(\s+)?([a-z\s]+?)(\s+)?"/gm;
const str = `"name","john","name of john"
"name","       john","name of john"
"       name  ","       john","name of john     "
"       name  ","       john","       name of john     "`;
const subst = `\n$2`;

// The substituted value will be contained in the result variable
const result = str.replace(regex, subst);

console.log('Substitution result: ', result);

任务 3

This expression可能会帮助你为第三个任务设计一个表达式:

(.*?)([a-z\s]+)(.*?)

const regex = /(.*?)([a-z\s]+)(.*?)/gm;
const str = `key = value // comment
key = value with some text // comment`;
const subst = `$2,`;

// The substituted value will be contained in the result variable
const result = str.replace(regex, subst);

console.log('Substitution result: ', result);