blocks|key|1193568|text|使用""+%2B+5+%2B+6将其强制为字符串。这也适用于数值变量：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1193569|​|1193570|var+a+=+5;
var+b+=+6;
console.log(""+%2B+a+%2B+b);|code-block|syntax|javascript|1193571|1193572|entityMap^0|2|A|0|0|0|0^^$0|@$1|2|3|4|5|6|7|P|8|@$9|Q|A|R|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|S|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|T|8|@]|D|@]|E|$K|L]]|$1|M|3|G|5|6|7|U|8|@]|D|@]|E|$]]|$1|N|3|-4|5|6|7|V|8|@]|D|@]|E|$]]]|O|$]]

Use <code>"" + 5 + 6</code> to force it to strings. This works with numerical variables too:

<div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
<div class="snippet-code">
<pre class="snippet-code-js lang-js prettyprint-override"><code>var a = 5;
var b = 6;
console.log("" + a + b);</code></pre>
</div>
</div>

blocks|key|1409407|text|现在可以使用ES6模板文字了。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1409408|const+numbersAsString+=+`${5}${6}`;
console.log(numbersAsString);+//+Outputs+56|code-block|syntax|javascript|1409409|或者，如果你有变量：|1409410|const+someNumber+=+5;
const+someOtherNumber+=+6;
const+numbersAsString+=+`${someNumber}${someOtherNumber}`;

console.log(numbersAsString);+//+Outputs+56|1409411|就我个人而言，我发现新的语法要清晰得多，尽管略显冗长。|1409412|entityMap|0|LINK|mutability|MUTABLE|url|http://es6-features.org/#StringInterpolation^0|6|3|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@$A|X|B|Y|1|Z]]|C|$]]|$1|D|3|E|5|F|7|10|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|11|8|@]|9|@]|C|$]]|$1|K|3|L|5|F|7|12|8|@]|9|@]|C|$G|H]]|$1|M|3|N|5|6|7|13|8|@]|9|@]|C|$]]|$1|O|3|-4|5|6|7|14|8|@]|9|@]|C|$]]]|P|$Q|$5|R|S|T|C|$U|V]]]]

You can now make use of <a href="http://es6-features.org/#StringInterpolation" rel="noreferrer">ES6</a> template literals.

<pre class="lang-js prettyprint-override"><code>const numbersAsString = `${5}${6}`;
console.log(numbersAsString); // Outputs 56
</code></pre>

Or, if you have variables:


<pre><code>const someNumber = 5;
const someOtherNumber = 6;
const numbersAsString = `${someNumber}${someOtherNumber}`;

console.log(numbersAsString); // Outputs 56
</code></pre>

Personally I find the new syntax much clearer, albeit slightly more verbose.

blocks|key|1193650|text|var+value+=+""+%2B+5+%2B+6;
alert(value);|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1193651|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>var value = "" + 5 + 6;
alert(value);
</code></pre>

blocks|key|1408967|text|只需使用：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1408968|5+%2B+""+%2B+6|code-block|syntax|javascript|1408969|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

just use:

<pre><code>5 + "" + 6
</code></pre>

blocks|key|1409634|text|我知道这是一个古老的帖子，已经被回复了很多次。我也想知道JavaScript是否有一个函数可以做到这一点。我正在做一些数学编程，需要连接两个数字。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1409635|那么，如果我需要将两个数字17和29组合在一起呢？当然，我可以将它们转换为字符串，并将它们连接起来，然后将新字符串转换回一个数字。这似乎工作得很好，我可以继续我的代码，但让我们看看这里，并试图弄清楚这里到底发生了什么。|1409636|我们对这两个数字做了什么，我们如何取17和29并将其转化为1,729？我们可以把17乘以100，然后再加29。那么172和293如何得到17万2293呢？将172乘以1000，再加上293。但是如果只有2和9呢？将2乘以10，然后加上9得到29。|1409637|因此，希望到目前为止，您应该清楚地看到了一种模式。我们可以设计一个数学公式来为我们做这个计算，而不仅仅是使用字符串。要连接任何两个数字，a和b，我们需要将a和10的乘积取为长度b的幂，然后将b相加。|1409638|那么我们如何得到数字b的长度呢？嗯，我们可以把b变成一个字符串，然后得到它的长度属性。|1409639|++++a+*+Math.pow(10,+new+String(b).length)+%2B+b;|code-block|syntax|javascript|1409640|但是有一种更好的方法可以在没有字符串的情况下做到这一点，对吧？是的有。|1409641|​|1409642|📷|atomic|offset|length|1409643|1409644|对于以B为底的任意两个数字，a和b，我们将a与底b相乘，乘以长度为b的幂(使用b的对数底，然后将其求底，以获得最接近的整数，然后将其加1)，然后再将b相加。|1409645|所以现在我们的代码看起来像这样：|1409646|++++a+*+Math.pow(10,+Math.floor(Math.log10(b))+%2B+1)+%2B+b;|1409647|但是等等，如果我想在基数2或基数8中这样做呢？我该怎么做呢？我们不能将我们刚刚创建的公式用于基数10以外的任何其他基数。JavaScript数学对象已经为基数10和2(只有Math.log)提供了内置函数，但是我们如何获得其他基数的日志函数？我们将b的log除以base的log。Math.log(b)+/+Math.log(base).|style|CODE|1409648|现在我们有了功能齐全的基于数学的代码来连接两个数字：|1409649|++++function+concatenate(a,+b,+base)+{
++++++++return+a+*+Math.pow(base,+Math.floor(Math.log(b)+/+Math.log(base))+%2B+1)+%2B+b;
++++}
++++var+a+=+17,+var+b+=+29;
++++var+concatenatedNumber+=+concatenate(a,+b,+10);
++++//+concatenatedNumber+=+1729|1409650|如果你知道你将只做基数10的数学运算，你可以添加一个对base+is+undefined的检查，然后设置base+=+10：|1409651|++++function+concatenate(a,+b,+base)+{
++++++++if(typeof+base+==+'undefined')+{
++++++++++++base+=+10;
++++++++}
++++++++return+a+*+Math.pow(base,+Math.floor(Math.log(b)+/+Math.log(base))+%2B+1)+%2B+b;
++++}

++++var+a+=+17,+b+=+29;
++++var+newNumber+=+concatenate(a,+b);+//+notice+I+did+not+use+the+base+argument
++++//+newNumber+=+1729|1409652|为了方便起见，我使用原型将函数添加到Number对象中：|1409653|++++Number.prototype.concatenate+=+function(b,+base)+{
++++++++if(typeof+base+==+'undefined')+{
++++++++++++++++base+=+10;
++++++++}
++++++++return+this+*+Math.pow(base,+Math.floor(Math.log(b)+/+Math.log(base))+%2B+1)+%2B+b;
++++};
++++var+a+=+17;
++++var+newNumber+=+a.concatenate(29);
++++//+newNumber+=+1729|1409654|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/213eeb2efefefd12ba153cae651dc171.png|imageAlt^0|0|0|0|0|0|0|0|0|0|1|0|0|0|0|0|0|3W|T|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|1T|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|1U|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|1V|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|1W|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|1X|8|@]|9|@]|A|$]]|$1|J|3|K|5|L|7|1Y|8|@]|9|@]|A|$M|N]]|$1|O|3|P|5|6|7|1Z|8|@]|9|@]|A|$]]|$1|Q|3|R|5|6|7|20|8|@]|9|@]|A|$]]|$1|S|3|T|5|U|7|21|8|@]|9|@$V|22|W|23|1|24]]|A|$]]|$1|X|3|R|5|6|7|25|8|@]|9|@]|A|$]]|$1|Y|3|Z|5|6|7|26|8|@]|9|@]|A|$]]|$1|10|3|11|5|6|7|27|8|@]|9|@]|A|$]]|$1|12|3|13|5|L|7|28|8|@]|9|@]|A|$M|N]]|$1|14|3|15|5|6|7|29|8|@$V|2A|W|2B|16|17]]|9|@]|A|$]]|$1|18|3|19|5|6|7|2C|8|@]|9|@]|A|$]]|$1|1A|3|1B|5|L|7|2D|8|@]|9|@]|A|$M|N]]|$1|1C|3|1D|5|6|7|2E|8|@]|9|@]|A|$]]|$1|1E|3|1F|5|L|7|2F|8|@]|9|@]|A|$M|N]]|$1|1G|3|1H|5|6|7|2G|8|@]|9|@]|A|$]]|$1|1I|3|1J|5|L|7|2H|8|@]|9|@]|A|$M|N]]|$1|1K|3|-4|5|6|7|2I|8|@]|9|@]|A|$]]]|1L|$1M|$5|1N|1O|1P|A|$1Q|1R|1S|-4]]]]

I know this is an old post and has been answered many times. I too was wondering if JavaScript had a function that would do this. I was doing some math programming and needed to concatenate two numbers.

So the what if I needed to combine two numbers 17 and 29. Sure I can turn them into strings and concatenate them then turn the new string back into a number. That seems to work pretty well and I can go on with my code, but lets take a look here and try to figure out what is really happening here.

What are we doing to these two numbers, how do we take 17 and 29 and turn it into one thousand seven hundred and twenty-nine? Well we can multiply 17 by 100 then add 29. And how about 172 and 293 to get one hundred seventy-two thousand two hundred and ninety-three? Multiply 172 by 1000 and add 293. But what about only 2 and 9? Multiply 2 by 10 then add 9 to get 29.

So hopefully by now a pattern should be apparent to you. We can devise a math formula to do this calculation for us rather than just using strings. To concatenate any two numbers, a and b, we need to take the product of a and 10 to the power of length b then add b.

So how do we get the length of number b? Well, we could turn b into a string and get the length property of it.

<pre><code> a * Math.pow(10, new String(b).length) + b;
</code></pre>

But there has to be a better way to do this without strings, right? Yes there is.

<a href="https://i.stack.imgur.com/4KsZr.png" rel="noreferrer"><img src="https://i.stack.imgur.com/4KsZr.png" alt="enter image description here"></a>

For any two numbers, a and b, with any base B. We are going to multiply a by base B to the power of length b (using log base of b then flooring it to get the nearest whole number then adding 1 to it) then adding b.

So now our code looks like this:

<pre><code> a * Math.pow(10, Math.floor(Math.log10(b)) + 1) + b;
</code></pre>

But wait, what if I wanted to do this in base 2 or base 8? How can I do that? We can't use our formula that we just created with any other base but base 10. The JavaScript Math object already has built-in functions for base 10 and 2 (just Math.log), but how do we get log functions for any other base? We divide the log of b by the log of base. <code>Math.log(b) / Math.log(base).</code>

So now we have our fully functioning math based code for concatenating two numbers:

<pre><code> function concatenate(a, b, base) {
 return a * Math.pow(base, Math.floor(Math.log(b) / Math.log(base)) + 1) + b;
 }
 var a = 17, var b = 29;
 var concatenatedNumber = concatenate(a, b, 10);
 // concatenatedNumber = 1729
</code></pre>

If you knew you were only going to be doing base 10 math, you could add a check for base is undefined then set base = 10:

<pre><code> function concatenate(a, b, base) {
 if(typeof base == 'undefined') {
 base = 10;
 }
 return a * Math.pow(base, Math.floor(Math.log(b) / Math.log(base)) + 1) + b;
 }

 var a = 17, b = 29;
 var newNumber = concatenate(a, b); // notice I did not use the base argument
 // newNumber = 1729
</code></pre>

To make it easier for me, I used the prototype to add the function to the Number object:

<pre><code> Number.prototype.concatenate = function(b, base) {
 if(typeof base == 'undefined') {
 base = 10;
 }
 return this * Math.pow(base, Math.floor(Math.log(b) / Math.log(base)) + 1) + b;
 };
 var a = 17;
 var newNumber = a.concatenate(29);
 // newNumber = 1729
</code></pre>

blocks|key|1193622|text|答案很简单：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1193623|5+%2B+''+%2B+6;|code-block|syntax|javascript|1193624|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

simple answer:

<pre><code>5 + '' + 6;
</code></pre>

blocks|key|1193664|text|var+output+=+5+%2B+''+%2B+6;|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1193665|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>var output = 5 + '' + 6;
</code></pre>

blocks|key|1409060|text|使用|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1409061|var+value+=+""+%2B+5+%2B+6;|code-block|syntax|javascript|1409062|将其强制为字符串。|1409063|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Use 

<pre><code>var value = "" + 5 + 6;
</code></pre>

to force it to strings.

blocks|key|1193977|text|您也可以使用toString函数将其转换为字符串并连接。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1193978|var+a+=+5;
var+b+=+6;
var+value+=+a.toString()+%2B+b.toString();|code-block|syntax|javascript|1193979|entityMap^0|6|8|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

You can also use <code>toString</code> function to convert it to string and concatenate.

<pre><code>var a = 5;
var b = 6;
var value = a.toString() + b.toString();
</code></pre>

blocks|key|1409112|text|另一种可能是：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1409113|var+concat+=+String(5)+%2B+String(6);|code-block|syntax|javascript|1409114|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Another possibility could be this:

<pre><code>var concat = String(5) + String(6);
</code></pre>

blocks|key|1194249|text|//+enter+code+here
var+a+=+9821099923;
var+b+=+91;
alert+(""+%2B+b+%2B+a);+
//+after+concating+,+result+is+919821099923+but+its+is+now+converted+into+string++

console.log(Number.isInteger(""+%2B+b+%2B+a))++//+false

//+you+have+to+do+something+like+this

var+c=+parseInt(""+%2B+b+%2B+a)
console.log(c);+//+919821099923
console.log(Number.isInteger(c))+//+true|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1194250|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>// enter code here
var a = 9821099923;
var b = 91;
alert (&quot;&quot; + b + a); 
// after concating , result is 919821099923 but its is now converted into string 

console.log(Number.isInteger(&quot;&quot; + b + a)) // false

// you have to do something like this

var c= parseInt(&quot;&quot; + b + a)
console.log(c); // 919821099923
console.log(Number.isInteger(c)) // true
</code></pre>

blocks|key|1193774|text|这是一种简单的方法|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1193775|var+value+=+5+%2B+""+%2B+6;|code-block|syntax|javascript|1193776|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

This is the easy way to do this
<pre><code>var value = 5 + &quot;&quot; + 6;
</code></pre>

blocks|key|1409739|text|我转换回了数字，如下所示。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1409740|const+timeNow+=+''+%2B+12+%2B+45;
const+openTime+=+parseInt(timeNow,+10);|code-block|syntax|javascript|1409741|输出1245|1409742|-编辑--|1409743|抱歉的,|1409744|对于我的使用，这在测试后仍然不起作用。我不得不重新添加丢失的零，因为它是在小于10的数字上被删除的，我的用途是让代码在某些时间运行可能不正确，但它似乎(到目前为止)是有效的。|1409745|h+=+new+Date().getHours();
m+=+new+Date().getMinutes();
isOpen:+boolean;

timeNow+=+(this.m+<+10)+?+''+%2B+this.h+%2B+0+%2B+this.m+:+''+%2B+this.h+%2B+this.m;

openTime+=+parseInt(this.timeNow);


closed()+{

(this.openTime+>=+1450+&&+this.openTime+<=+1830)+?+this.isOpen+=+true+:+
this.isOpen+=+false;
(this.openTime+>=+715+&&+this.openTime+<=+915)+?+this.isOpen+=+true+:+
this.isOpen+=+false;|1409746|}|1409747|投票结果很好，谢谢你:)|1409748|我是个新手，来这里是为了向你们学习解释为什么会很好。|1409749|总之，我更新了我的代码，展示了我是如何解决这个问题的，因为这篇文章帮助我解决了这个问题。|1409750|entityMap^0|0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|11|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|12|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|13|8|@]|9|@]|A|$]]|$1|K|3|L|5|6|7|14|8|@]|9|@]|A|$]]|$1|M|3|N|5|6|7|15|8|@]|9|@]|A|$]]|$1|O|3|P|5|D|7|16|8|@]|9|@]|A|$E|F]]|$1|Q|3|R|5|6|7|17|8|@]|9|@]|A|$]]|$1|S|3|T|5|6|7|18|8|@]|9|@]|A|$]]|$1|U|3|V|5|6|7|19|8|@]|9|@]|A|$]]|$1|W|3|X|5|6|7|1A|8|@]|9|@]|A|$]]|$1|Y|3|-4|5|6|7|1B|8|@]|9|@]|A|$]]]|Z|$]]

I converted back to number like this..

<pre><code>const timeNow = '' + 12 + 45;
const openTime = parseInt(timeNow, 10);
</code></pre>

output 1245

-- edit -- 

sorry,

for my use this still did not work for me after testing .
I had to add the missing zero back in as it was being removed on numbers smaller than 10, my use is for letting code run at certain times
May not be correct but it seems to work (so far).

<pre><code>h = new Date().getHours();
m = new Date().getMinutes();
isOpen: boolean;

timeNow = (this.m &lt; 10) ? '' + this.h + 0 + this.m : '' + this.h + this.m;

openTime = parseInt(this.timeNow);


closed() {

(this.openTime &gt;= 1450 &amp;&amp; this.openTime &lt;= 1830) ? this.isOpen = true : 
this.isOpen = false;
(this.openTime &gt;= 715 &amp;&amp; this.openTime &lt;= 915) ? this.isOpen = true : 
this.isOpen = false;
</code></pre>

}

The vote down was nice thank you :)

I am new to this and come here to learn from you guys an explanation of why would of been nice.

Anyways updated my code to show how i fixed my problem as this post helped me figure it out.

blocks|key|1194420|text|我更喜欢concat的方式：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1194421|const+numVar1+=+5;
const+numVar2+=+6;
const+value+=+"".concat(numVar1,+numVar2);
//+or+directly+with+values
const+value2+=+"".concat(5,+6);|code-block|syntax|javascript|1194422|您还可以使用在某些用例中提供帮助的数组：|1194423|const+value3+=+[5,+6,+numVar1].join('');|1194424|entityMap^0|4|6|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|T|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|U|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|V|8|@]|D|@]|E|$I|J]]|$1|O|3|-4|5|6|7|W|8|@]|D|@]|E|$]]]|P|$]]

I'd prefer the <code>concat</code> way :

<pre><code>const numVar1 = 5;
const numVar2 = 6;
const value = "".concat(numVar1, numVar2);
// or directly with values
const value2 = "".concat(5, 6);
</code></pre>

You can also use an array which can help in some use cases :

<pre><code>const value3 = [5, 6, numVar1].join('');
</code></pre>

I'd like for something like <code>5 + 6</code> to return <code>"56"</code> instead of <code>11</code>.

How to concatenate two numbers in javascript?

我希望像5 + 6这样的东西返回"56"而不是11。

问如何在javascript中连接两个数字？
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