On Fri, Oct 26, 2012 at 8:32 AM, Ed Morton <mortons...@gmail.com> wrote: > On 10/25/2012 11:45 PM, Rivka Miller wrote: >> >> Thanks everyone, esp this gentleman. >> >> The solution that worked best for me is just to use a DOT before the >> string as the one at the beginning of the line did not have any char >> before it. > > > That's fine but do you understand that that is not an RE that matches on > "$hello$ not at the start of a line", it's an RE that matches on "<any > char>$hello$ anywhere in the line"? There's a difference - if you use a tool > that prints the text that matches an RE then the output if the first RE > existed would be "$hello$" while the output for the second RE would be > "X$hello$" or "Y$hello$" or.... > > In some tools you can use /(.)$hello$/ or similar to ignore the first part > of the RE "(.)" and just print the second "$hello", but that ability and > it's syntax is tool-specific, you still can't say "here's an RE that does > this", you've got to say "here's how to find this text using tool > <whatever>". > > Ed. > > >> I guess, this requires the ability to ignore the CARAT as the beginning of >> the line. >> >> I am a satisfied custormer. No need for returns. :) >> >> On Oct 25, 7:11 pm, Ben Bacarisse <ben.use...@bsb.me.uk> wrote: >>> >>> Rivka Miller <rivkaumil...@gmail.com> writes: >>>> >>>> On Oct 25, 2:27 pm, Danny <dann90...@gmail.com> wrote: >>>>> >>>>> Why you just don't give us the string/input, say a line or two, and >>>>> what you want off of it, so we can tell better what to suggest >>> >>> >>>> no one has really helped yet. >>> >>> >>> Really? I was going to reply but then I saw Janis had given you the >>> answer. If it's not the answer, you should just reply saying what it is >>> that's wrong with it. >>> >>>> I want to search and modify. >>> >>> >>> Ah. That was missing from the original post. You can't expect people >>> to help with questions that weren't asked! To replace you will usually >>> have to capture the single preceding character. E.g. in sed: >>> >>> sed -e 's/\(.\)$hello\$/\1XXX/' >>> >>> but some RE engines (Perl's, for example) allow you specify zero-width >>> assertions. You could, in Perl, write >>> >>> s/(?<=.)\$hello\$/XXX/ >>> >>> without having to capture whatever preceded the target string. But >>> since Perl also has negative zero-width look-behind you can code your >>> request even more directly: >>> >>> s/(?<!^)\$hello\$/XXX/ >>> >>>> I dont wanna be tied to a specific language etc so I just want a >>>> regexp and as many versions as possible. Maybe I should try in emacs >>>> and so I am now posting to emacs groups also, although javascript has >>>> rich set of regexp facilities. >>> >>> >>> You can't always have a universal solution because different PE >>> implementations have different syntax and semantics, but you should be >>> able to translate Janis's solution of matching *something* before your >>> target into every RE implementation around. >>> >>>> examples >>> >>> >>>> $hello$ should not be selected but >>>> not hello but all of the $hello$ and $hello$ ... $hello$ each one >>>> selected >>> >>> >>> I have taken your $s to be literal. That's not 100 obvious since $ is a >>> common (universal?) RE meta-character. >>> >>> <snip> >>> -- >>> Ben. >> >> > > -- > http://mail.python.org/mailman/listinfo/python-list
I would use str.find('your string') It returns -1 if not found, and the index if it finds it. why use regex for this? -- Joel Goldstick -- http://mail.python.org/mailman/listinfo/python-list