Javascript：替换_后的字符
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Javascript: Replace characters after _
提问by TraderZed
I'm trying to do something which seems fairly basic, but can't seem to get it working.
我正在尝试做一些看起来相当基本的事情，但似乎无法让它发挥作用。
I'm trying to strip the characters after the last instance of an underscore.
我试图在下划线的最后一个实例之后去除字符。
I have this string, for example:
我有这个字符串，例如：
www/images/10/20120412/28-696-b0b9815463e47c9371b02b7202788a75_tn.jpg
www/images/10/20120412/28-696-b0b9815463e47c9371b02b7202788a75_tn.jpg
and I'm trying to strip out the 'tn.jpg' to produce:
我正在尝试去除 'tn.jpg' 以产生：
www/images/10/20120412/28-696-b0b9815463e47c9371b02b7202788a75_
www/images/10/20120412/28-696-b0b9815463e47c9371b02b7202788a75_
I tried doing .slice(0,-6) but that will only work for instances of _tn.jpg and not _med.jpg.
我尝试做 .slice(0,-6) 但这仅适用于 _tn.jpg 而不是 _med.jpg 的实例。
Ultimately, I'm going to be swapping in different sizes of images (_med.jpg, _full.jpg etc.) and it needs to be only after the last underscore (there might be underscores in the URL).
最终，我将交换不同大小的图像（_med.jpg、_full.jpg 等），并且只需要在最后一个下划线之后（URL 中可能有下划线）。
Any help would be greatly appreciated!
任何帮助将不胜感激！
Zack
扎克
回答by
You can it like this:
你可以这样：
var testURL = "dvuivnhuiv_ew";
var output = testURL.substring(0, testURL.lastIndexOf('_') + 1);
console.log(output);
回答by Patrick Lee Scott
var path = "www/images/10/20120412/28-696-b0b9815463e47c9371b02b7202788a75_tn.jpg";
var index = path.lastIndexOf('_');
path = path.substring(0, index+1);
alert(path);
