Replacing strings with regex in JavaScript
A particular regular expression is bugging me right now. I simply want to replace the range=100 in a string like
var string = '...commonstringblabla<b>&range=100&</b>stringandsoon...'开发者_如何学C;
with
...commonstringblabla<b>&range=400&</b>stringandsoon...
I successfully matched the "range=100"-part with
alert( string.match(/range=100/) );
But when I try to replace it,
string.replace(/range=100/, 'range=400');
nothing happens. The string still has the range=100 in it. How can I make it work?
string.replace isn't destructive, meaning, it doesn't change the instance it is called on.
To do this use
string = string.replace("range=100","range=400");
Because replace
does not modify the string it is applied on, but returns a new string.
string = string.replace(/range=100/, 'range=400');
I would do this:
string.replace(/([?&])range=100(?=&|$)/, '$1range=400')
This will only replace range=100
if it’s a URI argument (so it’s delimited on the left by either ?
or &
and on the right by &
or the end of the string).
I would do this way
string = string.replace(/\brange=100(?!\d)/, 'range=400');
Write only string.replace("range=100","range=400");
.
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