用replaceAll删除部分字符串

Question

I'm trying to delete the beginning of the following sentence from a file:

size:

size :

The issue is with the space between " : ". I have tried many regular expressions using some help from https://regex101.com/ but none of them works for me.

My code:

String myString= in.nextLine();
myString.replaceAll("size$:", "");
int n = Integer.parseInt(myString);

Answer 1

You can use this regex size\\s*: which mean replace size followed by zero or more spaces followed by : like so :

myString = myString.replaceAll("size\\s*:", "");

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regex demo

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Note that Strings in Java are immutable so you have to assign the result of replaceAll to your String else myString will not be changed even your replaceAll work fine.

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If you want to delete only the "size\\s:" strings from the beginning of your line, you can just add ^ anchor to your regex which mean beginning of line, so it will be like this :

myString = myString.replaceAll("^size\\s*:", "");

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regex demo