jQuery : Convert javascript array to string

2019-01-20 23:26发布

问题:

I'm trying to iterate over a "value" list and convert it into a string. Here is the code:

var blkstr = $.each(value, function(idx2,val2) {                    
     var str = idx2 + ":" + val2;
     alert(str);
     return str;
}).get().join(", ");    

alert() function works just fine and displays the proper value. But somehow, jquery's .get() function doesn't get the right sort of object and fails. What am I doing wrong?

回答1:

If value is associative array, such code will work fine:

var value = { "aaa": "111", "bbb": "222", "ccc": "333" };
var blkstr = [];
$.each(value, function(idx2,val2) {                    
  var str = idx2 + ":" + val2;
  blkstr.push(str);
});
console.log(blkstr.join(", "));
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script>

(output will appear in the dev console)

As Felix mentioned, each() is just iterating the array, nothing more.



回答2:

Converting From Array to String is So Easy !

var A = ['Sunday','Monday','Tuesday','Wednesday','Thursday']
array = A + ""

That's it Now A is a string. :)



回答3:

You can use .toString() to join an array with a comma.

var array = ['a', 'b', 'c'];
array.toString(); // result: a,b,c

Or, set the separator with array.join('; '); // result: a; b; c.



回答4:

not sure if this is what you wanted but

var arr = [A, B, C];
var arrString = arr.join(", ");

This results in the following output:

A, B, C



回答5:

Four methods to convert an array to a string.

Coercing to a string

var arr = ['a', 'b', 'c'] + [];  // "a,b,c"

var arr = ['a', 'b', 'c'] + '';  // "a,b,c"

Calling .toString()

var arr = ['a', 'b', 'c'].toString();  // "a,b,c"

Explicitly joining using .join()

var arr = ['a', 'b', 'c'].join();  // "a,b,c" (Defaults to ',' seperator)

var arr = ['a', 'b', 'c'].join(',');  // "a,b,c"

You can use other separators, for example, ', '

var arr = ['a', 'b', 'c'].join(', ');  // "a, b, c"

Using JSON.stringify()

This is cleaner, as it quotes strings inside of the array and handles nested arrays properly.

var arr = JSON.stringify(['a', 'b', 'c']);  // '["a","b","c"]'


回答6:

jQuery.each is just looping over the array, it doesn't do anything with the return value. You are looking for jQuery.map (I also think that get() is unnecessary as you are not dealing with jQuery objects):

var blkstr = $.map(value, function(val,index) {                    
     var str = index + ":" + val;
     return str;
}).join(", ");  

DEMO


But why use jQuery at all in this case? map only introduces an unnecessary function call per element.

var values = [];

for(var i = 0, l = value.length; i < l; i++) {
    values.push(i + ':' + value[i]);
}

// or if you actually have an object:

for(var id in value) {
    if(value.hasOwnProperty(id)) {
        values.push(id + ':' + value[id]);
    }
}

var blkstr = values.join(', ');

∆: It only uses the return value whether it should continue to loop over the elements or not. Returning a "falsy" value will stop the loop.



回答7:

this's my function, convert object or array to json

function obj2json(_data){
    str = '{ ';
    first = true;
    $.each(_data, function(i, v) { 
        if(first != true)
            str += ",";
        else first = false;
        if ($.type(v)== 'object' )
            str += "'" + i + "':" + obj2arr(v) ;
        else if ($.type(v)== 'array')
            str += "'" + i + "':" + obj2arr(v) ;
        else{
            str +=  "'" + i + "':'" + v + "'";
        }
    });
    return str+= '}';
}

i just edit to v0.2 ^.^

 function obj2json(_data){
    str = (($.type(_data)== 'array')?'[ ': '{ ');
    first = true;
    $.each(_data, function(i, v) { 
        if(first != true)
            str += ",";
        else first = false;
        if ($.type(v)== 'object' )
            str += '"' + i + '":' + obj2json(v) ;
        else if ($.type(v)== 'array')
            str += '"' + i + '":' + obj2json(v) ;
        else{
            if($.type(_data)== 'array')
                str += '"' + v + '"';
            else
                str +=  '"' + i + '":"' + v + '"';
        }
    });
    return str+= (($.type(_data)== 'array')? ' ] ':' } ');;
}


回答8:

var arr = new Array();

var blkstr = $.each([1, 2, 3], function(idx2,val2) {                    
    arr.push(idx2 + ":" + val2);
    return arr;
}).join(', ');

console.log(blkstr);

OR

var arr = new Array();

$.each([1, 2, 3], function(idx2,val2) {                    
    arr.push(idx2 + ":" + val2);

});

console.log(arr.join(', '));


回答9:

I needed an array to became a String rappresentation of an array I mean I needed that

var a = ['a','b','c'];
//became a "real" array string-like to pass on query params so was easy to do:
JSON.stringify(a); //-->"['a','b','c']"

maybe someone need it :)



回答10:

convert an array to a GET param string that can be appended to a url could be done as follows

function encodeGet(array){
    return getParams = $.map(array , function(val,index) {                    
        var str = index + "=" + escape(val);
        return str;
   }).join("&");
}

call this function as

var getStr = encodeGet({
    search:     $('input[name="search"]').val(),
    location:   $('input[name="location"]').val(),
    dod:        $('input[name="dod"]').val(),
    type:       $('input[name="type"]').val()
});
window.location = '/site/search?'+getStr;

which will forward the user to the /site/search? page with the get params outlined in the array given to encodeGet.



回答11:

Shouldn't confuse Array's with Lists... This is a list: {...} and has no length, or other Array properties.

This is an Array: [...] and you can use array functions, methods and so, like someone suggested here: someArray.toString();

"someObj.toString();" just will not work on any other objects type, like Lists. ;-)



回答12:

Array.prototype.toString()

The toString() method returns a string representing the specified array and its elements.

var months = ["Jan", "Feb", "Mar", "Apr"];
months.toString(); // "Jan,Feb,Mar,Apr"

Syntax

arr.toString()

Return value

A string representing the elements of the array.

for more information :

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/toString



回答13:

Here's an example using underscore functions.

var exampleArray = [{name: 'moe', age: 40}, {name: 'larry', age: 50}, {name: 'curly', age: 60}];
var finalArray = _.compact(_.pluck(exampleArray,"name")).join(",");

Final output would be "moe,larry,curly"