blocks|key|3276741|text|您可以使用正则表达式，也可以使用一些字符串方法来明确您的意图。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3276742|var+idx+=+myStr.lastIndexOf("-");
var+newStr+=+myStr.substring(0,+idx)+%2B+"big.png";|code-block|syntax|javascript|3276743|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|$]]

You could use a regex, or you could use a few string methods and make your intentions clear.

<pre><code>var idx = myStr.lastIndexOf("-");
var newStr = myStr.substring(0, idx) + "big.png";
</code></pre>

blocks|key|5488331|text|只需将'-‘添加到您的正则表达式和替换字符串：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5488332|myStr+=+myStr+.replace(/-([%5E-]*)\.png$/,+"-big.png");|code-block|syntax|javascript|5488333|或者，如果您希望文件扩展名是可变的：|5488334|myStr+=+myStr+.replace(/-([%5E-]*)\.([a-z]%2B)$/,+"-big.$2");|5488335|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

Just add '-' to your regex and to the replacement string:

<pre><code>myStr = myStr .replace(/-([^-]*)\.png$/, "-big.png");
</code></pre>

Or if you want the file extension to be variable:

<pre><code>myStr = myStr .replace(/-([^-]*)\.([a-z]+)$/, "-big.$2");
</code></pre>

blocks|key|5399072|text|我要承认:我对正则表达式也不太在行。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5399073|使用split拆分怎么样？不太简洁，但更容易理解。|offset|length|style|CODE|5399074|var+myStr+=+"/private_images/last-edit/image-work-med.png";​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​
var+strs+=+myStr.split('-');

//+Change+the+last+element.
strs[strs.length+-+1]+=+"big.png";

//+And+put+back+the+right+string.
myStr+=+strs.join('-');|code-block|syntax|javascript|5399075|entityMap^0|0|2|5|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@$D|Q|E|R|F|G]]|9|@]|A|$]]|$1|H|3|I|5|J|7|S|8|@]|9|@]|A|$K|L]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

I'll make a confession: I'm not so great with regexes either.

How about splitting up using <code>split</code>? Less concise, but easier to understand.

<pre><code>var myStr = "/private_images/last-edit/image-work-med.png";​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​
var strs = myStr.split('-');

// Change the last element.
strs[strs.length - 1] = "big.png";

// And put back the right string.
myStr = strs.join('-');
</code></pre>

blocks|key|5399091|text|为什么不直接使用replace：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5399092|var+myStr+=+"/private_images/last-edit/image-work-med.png";​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​

var+newStr+=+myStr.replace("med.png",+"big.png");|code-block|syntax|javascript|5399093|根据您问题中指定的要求，这就足够了。|5399094|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|$]]

Why not just use replace:

<pre><code>var myStr = "/private_images/last-edit/image-work-med.png";​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​

var newStr = myStr.replace("med.png", "big.png");
</code></pre>

According to the requirements specified in your question this would suffice.

blocks|key|5488415|text|在不使用RegExp的情况下，可以使用：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|5488416|var+str+=+"/private_images/last-edit/image-work-med.png"
+++,replace+=+'big.png'
+++,nwstr+=+str.slice(0,str.lastIndexOf('-')%2B1)%2Breplace;
//=>+nwstr+now+"/private_images/last-edit/image-work-big.png"|code-block|syntax|javascript|5488417|更具“功能性”：|5488418|var+nwstr+=+function(s){
++++++++++++++return+s.replace(s.substr(-7),'');}(
+++++++++++++++'/private_images/last-edit/image-work-med.png'
+++++++++++)%2B'big.png'|5488419|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|$]]

Without using <code>RegExp</code> you could use:

<pre><code>var str = "/private_images/last-edit/image-work-med.png"
 ,replace = 'big.png'
 ,nwstr = str.slice(0,str.lastIndexOf('-')+1)+replace;
//=&gt; nwstr now "/private_images/last-edit/image-work-big.png"
</code></pre>

More 'functional':

<pre><code>var nwstr = function(s){
 return s.replace(s.substr(-7),'');}(
 '/private_images/last-edit/image-work-med.png'
 )+'big.png'
</code></pre>

blocks|key|5488434|text|如果你想使用字符串函数-|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5488435|var+myStr+=+"/private_images/last-edit/image-work-med.png";
var+cleanedupStr+=+myStr.slice(0,+myStr.lastIndexOf("-"));|code-block|syntax|javascript|5488436|String.slice|offset|length|5488437|entityMap|0|LINK|mutability|MUTABLE|url|https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/String/slice^0|0|0|0|C|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@]|9|@$I|V|J|W|1|X]]|A|$]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|A|$]]]|L|$M|$5|N|O|P|A|$Q|R]]]]

If you want to use string functions -

<pre><code>var myStr = "/private_images/last-edit/image-work-med.png";
var cleanedupStr = myStr.slice(0, myStr.lastIndexOf("-"));
</code></pre>

<a href="https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/String/slice" rel="nofollow">String.slice</a>

blocks|key|5399173|text|如果您知道它将是一个.png文件：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5399174|var+ex+=+new+Regex(@"-\w*.png$");
var+myStr+=+"/private_images/last-edit/image-work-med.png";​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​
myStr+=+ex.Replace(myStr,+"-big.png");|code-block|syntax|javascript|5399175|这是工作，但如果它是一个jpg它不会…|5399176|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|$]]

If you know it will be a .png file:

<pre><code>var ex = new Regex(@"-\w*.png$");
var myStr = "/private_images/last-edit/image-work-med.png";​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​
myStr = ex.Replace(myStr, "-big.png");
</code></pre>

It works but if its a jpg it wont...

blocks|key|3276971|text|var+url+=+"/private_images/last-edit/image-work-med.png";+
var+index+=+url.lastIndexOf('-');
url+=+url.substring(0,+index%2B1);
var+url2+=+"big.png";
var+output+=+url.concat(url2);+alert(output);|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|3276972|看看这个|unstyled|3276973|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|J|8|@]|9|@]|A|$]]|$1|G|3|-4|5|F|7|K|8|@]|9|@]|A|$]]]|H|$]]

<pre><code>var url = "/private_images/last-edit/image-work-med.png"; 
var index = url.lastIndexOf('-');
url = url.substring(0, index+1);
var url2 = "big.png";
var output = url.concat(url2); alert(output);
</code></pre>

Check this

This is my code :

<pre><code>​var myStr = "/private_images/last-edit/image-work-med.png";​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​
</code></pre>

and I'd like to replace the last 7 chars (<code>med.png</code>) with <code>big.png</code>. Or, as you can see, the last occurence after a <code>-</code> split.

How can I do it? I think about regex, but I'm not a champion with them. Tried :

<pre><code>myStr = myStr .replace(/-([^-]*)$/, "big" + '$1');
</code></pre>

but it replace the last <code>-</code>, not the last occurence. So the result is <code>/private_images/last-edit/image-workbigmed.png</code>

Replace a string of the last 7 chars?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

文章

问答

视频

学习中心

腾讯云实验室

直播

竞赛

腾讯云代码分析专区

腾讯iOA零信任安全管理系统专区

腾讯云架构师技术同盟交流圈

腾讯云数据库专区

腾讯云顾问专区

腾讯云原生专区

腾讯混元专区

腾讯云TCE专区

腾讯云Lighthouse专区

腾讯云HAI专区

腾讯云Edgeone专区

腾讯云存储专区

腾讯云智能专区

腾讯轻联专区 

腾讯云开发专区

TAPD专区

腾讯轻量云游戏服专区

腾讯云最具价值专家

腾讯云架构师技术同盟

腾讯云创作之星

腾讯云开发者先锋

腾讯云代码助手

云原生构建

TAPD 敏捷项目管理

Cloud Studio

SDK中心

API中心

命令行工具

涵盖代码开发、场景应用、自动测试全流程，助你从零构建专属AI助手

一站式MCP教程库，解锁AI应用新玩法

这是我的代码：​var myStr = "/private_images/last-edit/image-work-med.png";​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​我想用big.png替换最后7个字符(med.png)。或者，正如您所看到的，是-拆分后的最后一个事件。我该...

问是否替换最后7个字符的字符串？
EN

Stack Overflow用户

社区

活动

圈层

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问是否替换最后7个字符的字符串？EN