Regex performance Given a string like `field1="x" ...

# random

[Davide Giuseppe Farella]

Regex performance
Given a string like field1="x" field2="y" field3="z", how can a single regex that matches the 3 field be almost 2x slower than a indexOf( paramName ) - substring( index ) - split( '"' ) [1]?
Do you use regex for this purpose? I'm just exploring them for the first time.

[Marc Knaup]

Regular expressions are extremely powerful with plenty of complex functionality.
Unfortunately that also makes their implementation really difficult, complex and thus it's hard to get the best performance out of it.

[Davide Giuseppe Farella]

Thanks for the explanation, but does that mean I used it wrong or just it couldn't be better than the "verbose" method?

[hudsonb]

What's the regular expression you used? Maybe that could be optimized.

[Davide Giuseppe Farella]

tvg-id="([^\\"]*)".*group-title="([^\\"]*)".*tvg-logo="([^\\"]*)",(.*)

[Davide Giuseppe Farella]

They're 4 params for iptv playlist

[Marc Knaup]

Replace the first two .* with .*?

[Marc Knaup]

It may make things better. Or worse.
http://blog.stevenlevithan.com/archives/greedy-lazy-performance

[Davide Giuseppe Farella]

Thanks, I'll try tomorrow and keep you up to date