📘str.match()

str.match() 的回傳值有三種模式：

-----------------------------------------------
   matched   /g    return value    capture groups
-----------------------------------------------
1. ✅ 	     ✅     all matches	   ❌
2. ✅        ❌     first match     ✅
3. ❌               null
-----------------------------------------------

1. global mode (with /g set): return array of all matches (without info about capturing groups)

2. non-global mode (with /g not set): return array of first match (including additional info about capturing groups)

3. no match: return null.

💾 程式

👉 replit

//                       first match ↴
//             0         1         2         3         4
//      index: 01234567890123456789012345678901234567890
//                                   ╭── first match ──╮
const found = 'For more information, see Chapter 3.4.5.1'.match(
//                                       ╰─── group ───╯
    /see (chapter \d+(\.\d)*)/i     // ignore case, non-global
);

// ⭐️ three modes of str.match(regex) method's return value

log(found);
// ⭐️ 2. non-gloabl mode:
//   (return array of informations about first match)
// [
//   'see Chapter 3.4.5.1',         // whole match
//   'Chapter 3.4.5.1',             // first capture group ⭐️
//   '.1',                          // last value captured by '(\.\d)'
//   index: 22,                     // index of the whole match
//   input: 'For more information, see Chapter 3.4.5.1',    // original string
//   groups: undefined              // object of named capturing groups
// ]

let str = "We will, we will rock you";

// ⭐️ 1. global mode:
//   (return array of all matches, no capturing groups)
str.match(/we/gi),      // [ 'We', 'we' ]

// ⭐️ 3. no match:
//    (return null)
str.match(/they/),      // null ⭐️

💈範例

• split into course names

⬇️ 應用

• A1NotationToRowColumn() - "AA3" to [ "AA", "3" ].

📘 手冊

• String ⟩

  • .match()

  • .replace() ⟩ replacer function

👥 相關

• RegExp

• str.replace()

• str.matchAll()