- 替換第一個
var replaceAll = function(s, old_str, new_str) {
var str = s;
var index = s.indexOf(old_str);
if (index > 0) {
var head = s.slice(0, index);
var tail = s.slice(index + old_str.length);
str = head + new_str + tail;
}
console.log(str);
return str;
}
// 測試函數(shù)
replaceAll("abcdgbcjh0", "bc", "_"); // a_dgbcjh0
這段代碼相當(dāng)于用原生 JavaScript 實(shí)現(xiàn)"abcdgbcjh0".replace("bc", "_")
- 替換最后一個
// 查找子字符串在母字符串中的所有位置
var findIndex = function(s1, s2) {
var len = s2.length;
var arr = new Array();
for (var i = 0; i < s1.length; i++) {
var s = s1.slice(i, i + len);
if (s === s2) {
arr.push(i);
}
}
return arr;
}
var replaceLast = function(s, old_str, new_str) {
var oldList = findIndex(s, old_str);
var str = s;
if (oldList.length > 0) {
var index = oldList[oldList.length - 1];
var head = str.slice(0, index);
var tail = str.slice(index + old_str.length);
str = head + new_str + tail;
}
console.log(str);
return str;
}
replaceLast("abcdgbcjh0", "bc", "_"); // abcdg_jh0
- 替換所有
var replaceAll = function(s, old_str, new_str) {
var all_old = new RegExp(old_str, "g");
var str = s.replace(all_old, new_str);
console.log(str);
return str;
}
// 測試函數(shù)
replaceAll("abcdgbcjhbc0", "bc", "_"); // a_dg_jh_0
replaceAll(" ", "bc", "_"); // 返回一個空格
