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本文小編為大家詳細介紹“JavaScript常用字符串與數組擴展函數有哪些”，內容詳細，步驟清晰，細節處理妥當，希望這篇“JavaScript常用字符串與數組擴展函數有哪些”文章能幫助大家解決疑惑，下面跟著小編的思路慢慢深入，一起來學習新知識吧。
String對象的擴展函數：
String.prototype.trim = function() {
return this.replace(/^\s+|\s+$/g,"");
}
String.prototype.ltrim = function() {
return this.replace(/^\s+/g,"");
}
String.prototype.rtrim = function() {
return this.replace(/\s+$/g,"");
}
String.prototype.splitAndTrim = function($delimiter, $limit)
{
var $ss = this.split($delimiter, $limit);
for(var $i=0; $i<$ss.length; $i++)
$ss[$i] = $ss[$i].trim();
return $ss;
}
String.prototype.htmlEntities = function () {
return this.replace(/&/g,'&').replace(/</g,'<').replace(/>/g,'>');
}
String.prototype.stripTags = function () {
return this.replace(/<([^>]+)>/g,'');
}
String.prototype.toArray = function() {
return this.split('');
}
String.prototype.toIntArray = function() {
var returnArray = [];
for (var i=0; i<this.length; i++) {
returnArray.push(this.charCodeAt(i));
}
return returnArray;
}
String.prototype.replaceAll = function($old, $snew){
return this.replace(new RegExp($old,"gm"),$snew);
}變量替換
var a = "I Love {0}, and You Love {1},Where are {0}!";a.format("You","Me");
String.prototype.format = function(){
var args = arguments;
return this.replace(/\{(\d+)\}/g,function(m,i,o,n){
return args[i];
});
}在字符串末尾追加字符串
String.prototype.append = function($str){
return this.concat($str);
}刪除指定索引位置的字符，索引無效將不刪除任何字符
String.prototype.deleteCharAt = function($sIndex){
if($sIndex<0 || $sIndex>=this.length){
return this.valueOf();
}else if($sIndex==0){
return this.substring(1,this.length);
}else if($sIndex==this.length-1){
return this.substring(0,this.length-1);
}else{
return this.substring(0,$sIndex)+this.substring($sIndex+1);
}
}刪除指定索引間的字符串.$sIndex和$eIndex所在的字符不被刪除！依賴deleteCharAt
String.prototype.deleteString = function($sIndex, $eIndex){
if($sIndex==$eIndex){
return this.deleteCharAt($sIndex);
}else{
if($sIndex>$eIndex){
var tIndex=$eIndex;
$eIndex=$sIndex;
$sIndex=tIndex;
}
if($sIndex<0)$sIndex=0;
if($eIndex>this.length-1)$eIndex=this.length-1;
return this.substring(0,$sIndex+1)+this.substring($eIndex,this.length);
}
}檢查字符串是否以某個字符串(str)結尾
String.prototype.endsWith = function($str){
return this.substr(this.length - $str.length) == $str;
}檢查該字符串是否以某個字符串開始
String.prototype.startsWith = function(str){
return this.substr(0, str.length) == str;
}比較兩個字符串是否相等，不區分大小寫!
String.prototype.equalsIgnoreCase = function($str){
if(this.length!=$str.length){
return false;
}else{
var tmp1=this.toLowerCase();
var tmp2=$str.toLowerCase();
return tmp1==tmp2;
}
}將指定的字符串插入到指定的位置后面!索引無效將直接追加到字符串的末尾
String.prototype.insert = function($ofset, $str){
if($ofset<0 || $ofset>=this.length-1){
return this.concat($str);
}
return this.substring(0,$ofset)+$str+this.substring($ofset+1);
}將指定的位置的字符設置為另外指定的字符或字符串.索引無效將直接返回不做任何處理！
String.prototype.setCharAt = function($ofset, $str){
if($ofset<0 || $ofset>=this.length-1){
return this.valueOf();
}
return this.substring(0,$ofset)+$str+this.substring($ofset+1);
}
String.prototype.replaceLen = function(start, len, replaced) {
if(!len)
return this;
if(start >= this.length)
return this;
var returnSeg = '';
var returnSeg2 = '';
var i = 0;
for (; i < this.length; i++){
var c = this.charAt(i);
if(i < start)
returnSeg += c;
if(i >= start + len)
returnSeg2 += c;
}
return returnSeg + replaced + returnSeg2;
}擴展基礎類：
替換字符，這個在替換填入比較有用，比如***天***小時 替換為 <input />天<input />小時
String.prototype.replaceChar = function(target, replaced, start) {
if(!target)
return this;
if(!start)
start = 0;
var returnVal = this.substring(0, start);
var index = 0;
for (var i = start; i < this.length; i++) {
var c = this.charAt(i);
target = typeof target == 'function' ? target.call(this, index) : target;
if (c == target) {
returnVal += typeof replaced == 'function' ? replaced.call(this, index) : replaced;
while (i < this.length - 1 && this.charAt(i + 1) == c) {
i++;
}
index++;
}else{
returnVal += c;
}
}
return returnVal;
}將該字符串反序排列
String.prototype.reverse = function(){
var str="";
for(var i=this.length-1;i>=0;i--){
str=str.concat(this.charAt(i));
}
return str;
}計算長度，每個漢字占兩個長度，英文字符每個占一個長度
String.prototype.ucLength = function(){
var len = 0;
for(var i=0;i<this.length;i++){
if(this.charCodeAt(i)>255)len+=2;
else len++;
}
return len;
}在字符串的左邊填充一些特定的字符
String.prototype.lpad = function(len, s) {
var a = new Array(this);
var n = (len - this.length);
for ( var i = 0; i < n; i++) {
a.unshift(s);
}
return a.join("");
}在字符串的右邊填充一些特定的字符
String.prototype.rpad = function(len, s) {
var a = new Array(this);
var n = (len - this.length);
for ( var i = 0; i < n; i++) {
a.push(s);
}
return a.join("");
}把字符串的首字母轉化為大寫
String.prototype.ucwords = function() {
return this.substring(0,1).toUpperCase().concat(this.substring(1));
}
String.prototype.contains = function($str) {
return this.indexOf($str) > -1 ? true : false;
}將格式為2008-04-02 10:08:44的字符串轉成日期(String對象的值必須為: 2008-04-02 10:08:44)
String.prototype.toDate = function(){
var str = this.replace(/-/g,"/");
return (new Date(str));
}將原來用字符串表示的十進數轉成十進制浮點數: precision為精度
String.prototype.toFloat = function(precision){
precision = precision || 2;
return parseFloat(this,10).toFixed(precision);
}將原來用字符串表示的十進數轉成十進制整數
String.prototype.toInt = function(){
return parseInt(this,10).toString();
}將兩個原來用字符串表示的十進數相加后當作字串返回 : addend為加數
String.prototype.add = function(addend){
var sum = parseFloat(this,10) + parseFloat(addend,10);
return sum+"";
}十進制轉其他進制代碼如下nextScale為進制 如2,8,16
String.prototype.shiftScale = function(nextScale){
return parseFloat(this).toString(nextScale);
}
各進制互相轉換 ：
this對象必須是整數
@param preScale 原是是幾進制數
@param nextScale 要轉換成幾進制數
String.prototype.scaleShift = function(preScale,nextScale){
return parseInt(this,preScale).toString(nextScale);
}全角2半角 document.write("ＡＢＣ １２３，我們都是好朋友");
String.prototype.dbc2sbc = function (){
return this.replace(/[\uff01-\uff5e]/g,function(a){return String.fromCharCode(a.charCodeAt(0)-65248);}).replace(/\u3000/g," ");
}
Array擴展函數：
var isNumeric = function(x) {
// returns true if x is numeric and false if it is not.
var RegExp = /^(-)?(\d*)(\.?)(\d*)$/;
return String(x).match(RegExp);
}
var myArray = [1,'two',3,'four',5,'six',7,'eight',9,'ten'];
var oddArray=myArray.filter(isNumeric); // outputs: 1,3,5,7,9
var oddArray=myArray.some(isNumeric); // outputs: true
var oddArray=myArray.every(isNumeric); // outputs: false
var printArray =function(x, idx){
document.writeln('['+idx+'] = '+x);
}
myArray.forEach(printArray);// outputs: [0] = 1 [1] = two [2] = 3 [3] = four [4] = 5
myArray.remove(9);
document.writeln(myArray);
if (!Array.prototype.every)
{
Array.prototype.every = function(fun /*, thisp*/)
{
var len = this.length;
if (typeof fun != "function")
throw new TypeError();
var thisp = arguments[1];
for (var i = 0; i < len; i++)
{
if (i in this &&
!fun.call(thisp, this[i], i, this))
return false;
}
return true;
};
}
if (!Array.prototype.filter)
{
Array.prototype.filter = function(fun /*, thisp*/)
{
var len = this.length;
if (typeof fun != "function")
throw new TypeError();
var res = new Array();
var thisp = arguments[1];
for (var i = 0; i < len; i++)
{
if (i in this)
{
var val = this[i]; // in case fun mutates this
if (fun.call(thisp, val, i, this))
res.push(val);
}
}
return res;
};
}
if (!Array.prototype.forEach)
{
Array.prototype.forEach = function(fun /*, thisp*/)
{
var len = this.length;
if (typeof fun != "function")
throw new TypeError();
var thisp = arguments[1];
for (var i = 0; i < len; i++)
{
if (i in this)
fun.call(thisp, this[i], i, this);
}
};
}
if (!Array.prototype.map)
{
Array.prototype.map = function(fun /*, thisp*/)
{
var len = this.length;
if (typeof fun != "function")
throw new TypeError();
var res = new Array(len);
var thisp = arguments[1];
for (var i = 0; i < len; i++)
{
if (i in this)
res[i] = fun.call(thisp, this[i], i, this);
}
return res;
};
}
if (!Array.prototype.some)
{
Array.prototype.some = function(fun /*, thisp*/)
{
var len = this.length;
if (typeof fun != "function")
throw new TypeError();
var thisp = arguments[1];
for (var i = 0; i < len; i++)
{
if (i in this &&
fun.call(thisp, this[i], i, this))
return true;
}
return false;
};
}
Array.prototype.sortNum = function() {
return this.sort( function (a,b) { return a-b; } );
}
<!--
var tmp = [5,9,12,18,56,1,10,42,'blue',30, 7,97,53,33,30,35,27,30,'35','Ball', 'bubble'];
var thirty=tmp.find(30); // Returns 9, 14, 17
var thirtyfive=tmp.find('35'); // Returns 18
var thirtyfive=tmp.find(35); // Returns 15
var haveBlue=tmp.find('blue'); // Returns 8
var notFound=tmp.find('not there!'); // Returns false
var regexp1=tmp.find(/^b/); // returns 8,20 (first letter starts with b)
var regexp1=tmp.find(/^b/i); // returns 8,19,20 (same as above but ignore case)
-->
Array.prototype.find = function(searchStr) {
var returnArray = false;
for (i=0; i<this.length; i++) {
if (typeof(searchStr) == 'function') {
if (searchStr.test(this[i])) {
if (!returnArray) { returnArray = [] }
returnArray.push(i);
}
} else {
if (this[i]===searchStr) {
if (!returnArray) { returnArray = [] }
returnArray.push(i);
}
}
}
return returnArray;
}隨機改變數組的排序
Array.prototype.shuffle = function (){
for(var rnd, tmp, i=this.length; i; rnd=parseInt(Math.random()*i), tmp=this[--i], this[i]=this[rnd], this[rnd]=tmp);
return this;
}
<!--var myArray = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15];
var yourArray = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15];
document.writeln(myArray.compare(yourArray)); // outputs: true;-->
Array.prototype.compare = function(testArr) {
if (this.length != testArr.length) return false;
for (var i = 0; i < testArr.length; i++) {
if (this[i].compare) {
if (!this[i].compare(testArr[i])) return false;
}
if (this[i] !== testArr[i]) return false;
}
return true;
}去掉數組中重復的值var a = new Array("5","7","7"); a.unique();
Array.prototype.unique = function() {
var data = this || [];
var a = {}; //聲明一個對象，javascript的對象可以當哈希表用
for (var i = 0; i < data.length; i++) {
a[data[i]] = true; //設置標記，把數組的值當下標，這樣就可以去掉重復的值
}
data.length = 0;
for (var i in a) { //遍歷對象，把已標記的還原成數組
this[data.length] = i;
}
return data;
}
Array.prototype.addAll = function($array)
{
if($array == null || $array.length == 0)
return;
for(var $i=0; $i<$array.length; $i++)
this.push($array[$i]);
}
Array.prototype.contains = function($value)
{
for(var $i=0; $i<this.length; $i++)
{
var $element = this[$i];
if($element == $value)
return true;
}
return false;
}
Array.prototype.indexOf = function($value)
{
for(var $i=0; $i<this.length; $i++)
{
if(this[$i] == $value)
return $i;
}
return -1;
}
if (!Array.prototype.lastIndexOf)
{
Array.prototype.lastIndexOf = function(elt /*, from*/)
{
var len = this.length;
var from = Number(arguments[1]);
if (isNaN(from))
{
from = len - 1;
}
else
{
from = (from < 0)
? Math.ceil(from)
: Math.floor(from);
if (from < 0)
from += len;
else if (from >= len)
from = len - 1;
}
for (; from > -1; from--)
{
if (from in this &&
this[from] === elt)
return from;
}
return -1;
};
}
Array.prototype.insertAt = function($value, $index)
{
if($index < 0)
this.unshift($value);
else if($index >= this.length)
this.push($value);
else
this.splice($index, 0, $value);
}
根據數組的下標來刪除元素
Array.prototype.removeByIndex=function($n) {
if($n<0){ //如果n<0，則不進行任何操作。
return this;
}else{
return this.slice(0,$n).concat(this.slice($n+1,this.length));
}
}依賴indexOf
Array.prototype.remove = function($value)
{
var $index = this.indexOf($value);
if($index != -1)
this.splice($index, 1);
}
Array.prototype.removeAll = function()
{
while(this.length > 0)
this.pop();
}
Array.prototype.replace = function($oldValue, $newValue)
{
for(var $i=0; $i<this.length; $i++)
{
if(this[$i] == $oldValue)
{
this[$i] = $newValue;
return;
}
}
}
Array.prototype.swap = function($a, $b)
{
if($a == $b)
return;
var $tmp = this[$a];
this[$a] = this[$b];
this[$b] = $tmp;
}
Array.prototype.max = function() {
return Math.max.apply({}, this);
}
Array.prototype.min = function() {
return Math.min.apply({}, this);
}
Array.prototype.splice = function(start, delLen, item){
var len =this.length;
start = start<0?0:start>len?len:start?start:0;
delLen=delLen<0?0:delLen>len?len:delLen?delLen:len;
var arr =[],res=[];
var iarr=0,ires=0,i=0;
for(i=0;i<len;i++){
if(i<start|| ires>=delLen) arr[iarr++]=this[i];
else {
res[ires++]=this[i];
if(item&&ires==delLen){
arr[iarr++]=item;
}
}
}
if(item&&ires<delLen) arr[iarr]=item;
for(var i=0;i<arr.length;i++){
this[i]=arr[i];
}
this.length=arr.length;
return res;
}
Array.prototype.shift = function(){ if(!this) return[];return this.splice(0,1)[0];}
分開添加,關鍵字shallow copy,如果遇到數組，復制數組中的元素
Array.prototype.concat = function(){
var i=0;
while(i<arguments.length){
if(typeof arguments[i] === 'object'&&typeof arguments[i].splice ==='function' &&!arguments[i].propertyIsEnumerable('length')){
// NOT SHALLOW COPY BELOW
// Array.prototype.concat.apply(this,arguments[i++]);
var j=0;
while(j<arguments[i].length) this.splice(this.length,0,arguments[i][j++]);
i++;
} else{
this[this.length]=arguments[i++];
}
}
return this;
}
Array.prototype.join = function(separator){
var i=0,str="";
while(i<this.length) str+=this[i++]+separator;
return str;
}
Array.prototype.pop = function() { return this.splice(this.length-1,1)[0];}
Array.prototype.push = function(){
Array.prototype.splice.apply(this,
[this.length,0].concat(Array.prototype.slice.apply(arguments))); //這里沒有直接處理參數，而是復制了一下
return this.length;
}
Array.prototype.reverse = function(){
for(var i=0;i<this.length/2;i++){
var temp = this[i];
this[i]= this[this.length-1-i];
this[this.length-1-i] = temp;
}
return this;
}
Array.prototype.slice = function(start, end){
var len =this.length;
start=start<0?start+=len:start?start:0;
end =end<0?end+=len:end>len?len:end?end:len;
var i=start;
var res = [];
while(i<end){
res.push(this[i++]);
}
return res;
}
//arr.unshift(ele1,ele2,ele3....)
Array.prototype.unshift =function(){
Array.prototype.splice.apply(this,[0,0].concat(Array.prototype.slice.apply(this,arguments)));
}讀到這里，這篇“JavaScript常用字符串與數組擴展函數有哪些”文章已經介紹完畢，想要掌握這篇文章的知識點還需要大家自己動手實踐使用過才能領會，如果想了解更多相關內容的文章，歡迎關注億速云行業資訊頻道。
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