如何在JavaScript中删除数组中的空元素?
是否有一种简单的方法,或者我需要循环并手动删除它们?
如何在JavaScript中删除数组中的空元素?
是否有一种简单的方法,或者我需要循环并手动删除它们?
当前回答
几个简单的方法:
var arr = [1,2,,3,,-3,null,,0,,undefined,4,,4,,5,,6,,,,];
arr.filter(n => n)
// [1, 2, 3, -3, 4, 4, 5, 6]
arr.filter(Number)
// [1, 2, 3, -3, 4, 4, 5, 6]
arr.filter(Boolean)
// [1, 2, 3, -3, 4, 4, 5, 6]
或-(仅适用于“text”类型的单个数组项)
['','1','2',3,,'4',,undefined,,,'5'].join('').split('');
// output: ["1","2","3","4","5"]
或-经典方式:简单迭代
var arr = [1,2,null, undefined,3,,3,,,0,,,[],,{},,5,,6,,,,],
len = arr.length, i;
for(i = 0; i < len; i++ )
arr[i] && arr.push(arr[i]); // copy non-empty values to the end of the array
arr.splice(0 , len); // cut the array and leave only the non-empty values
// [1,2,3,3,[],Object{},5,6]
jQuery:
var arr = [1,2,,3,,3,,,0,,,4,,4,,5,,6,,,,];
arr = $.grep(arr, n => n == 0 || n);
// [1, 2, 3, 3, 0, 4, 4, 5, 6]
其他回答
如果有人想要清理整个阵列或对象,这可能会有所帮助。
var qwerty = {
test1: null,
test2: 'somestring',
test3: 3,
test4: {},
test5: {
foo: "bar"
},
test6: "",
test7: undefined,
test8: " ",
test9: true,
test10: [],
test11: ["77","88"],
test12: {
foo: "foo",
bar: {
foo: "q",
bar: {
foo:4,
bar:{}
}
},
bob: {}
}
}
var asdfg = [,,"", " ", "yyyy", 78, null, undefined,true, {}, {x:6}, [], [2,3,5]];
function clean_data(obj) {
for (var key in obj) {
// Delete null, undefined, "", " "
if (obj[key] === null || obj[key] === undefined || obj[key] === "" || obj[key] === " ") {
delete obj[key];
}
// Delete empty object
// Note : typeof Array is also object
if (typeof obj[key] === 'object' && Object.keys(obj[key]).length <= 0) {
delete obj[key];
}
// If non empty object call function again
if(typeof obj[key] === 'object'){
clean_data(obj[key]);
}
}
return obj;
}
var objData = clean_data(qwerty);
console.log(objData);
var arrayData = clean_data(asdfg);
console.log(arrayData);
输出:
删除任何null、undefined、“”、“”空对象或空数组
jsfiddle在这里
您可能会发现,循环遍历数组并使用要从数组中保留的项构建新数组比按照建议进行循环和拼接更容易,因为在循环遍历时修改数组的长度可能会带来问题。
你可以这样做:
function removeFalsyElementsFromArray(someArray) {
var newArray = [];
for(var index = 0; index < someArray.length; index++) {
if(someArray[index]) {
newArray.push(someArray[index]);
}
}
return newArray;
}
实际上,这里有一个更通用的解决方案:
function removeElementsFromArray(someArray, filter) {
var newArray = [];
for(var index = 0; index < someArray.length; index++) {
if(filter(someArray[index]) == false) {
newArray.push(someArray[index]);
}
}
return newArray;
}
// then provide one or more filter functions that will
// filter out the elements based on some condition:
function isNullOrUndefined(item) {
return (item == null || typeof(item) == "undefined");
}
// then call the function like this:
var myArray = [1,2,,3,,3,,,,,,4,,4,,5,,6,,,,];
var results = removeElementsFromArray(myArray, isNullOrUndefined);
// results == [1,2,3,3,4,4,5,6]
你明白了——你可以有其他类型的过滤函数。可能比你需要的更多,但我感觉很慷慨…;)
使用正则表达式筛选出无效条目
array = array.filter(/\w/);
filter + regexp
简单ES6
['a','b','',,,'w','b'].filter(v => v);
美好的很不错的我们也可以像这样替换所有数组值
Array.prototype.ReplaceAllValues = function(OldValue,newValue)
{
for( var i = 0; i < this.length; i++ )
{
if( this[i] == OldValue )
{
this[i] = newValue;
}
}
};