Gsub?

Ruby
1

I don’t manage very well the gsub function, not too bad with simple
one, but when it comes to string containing slashes, I totally mess it…

my string can be srt = “/cities/31550/posts;search”

and I would like
1- detect that srt is a string of this type /cities/ nnnnn
/posts;search" where nnnnn is a number between 1 and 99999

2- if srt is of this type, then replace the number nnnnn by another one
ppppp

don’t know how to do that in one DRY command…

thanks to the gsub guru …

btw : what’s the best link to learn more abour gsub… ?

2

Josselin wrote:

I don’t manage very well the gsub function, not too bad with simple
one, but when it comes to string containing slashes, I totally mess it…

Use %r{your_regex} instead of /your_regex/ - then you don’t have to
escape the
slashes.

my string can be srt = “/cities/31550/posts;search”

and I would like
1- detect that srt is a string of this type /cities/ nnnnn
/posts;search" where nnnnn is a number between 1 and 99999

%r{/cities/(\d{1,5})/posts;search}
\d{1,5} is “one to five digits” and the parens tell it to remember that
as
group 1.

2- if srt is of this type, then replace the number nnnnn by another one
ppppp

srt.sub(%r{/cities/(\d{1,5})/posts;search}) do
new_number=$1.to_i * 2 # (Or however the new number is calculated)
“/cities/#{new_number}/posts;search”
end
If the new number is fixed (i.e. it doesn’t depend on the old number),
you can
just do:
srt[%r{/cities/(\d{1,5})/posts;search},1]=“102943”

btw : what’s the best link to learn more abour gsub… ?

There’s not much to gsub itself. It’s just string.gsub(re,str) or
string.gsub(re) {|match| do_something; return a string}
What you want to learn more about are regular expressions.
You can do that at at www.regular-expressions.info

HTH,
Sebastian

3

On 2007-09-01 19:53:01 +0200, Sebastian H.
[email protected] said:

1- detect that srt is a string of this type /cities/ nnnnn
new_number=$1.to_i * 2 # (Or however the new number is calculated)
What you want to learn more about are regular expressions.
You can do that at at www.regular-expressions.info

HTH,
Sebastian

Thanks a lot you made my SUnday !!