<[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] > Hey there, > i have a text file with a bunch of values scattered throughout it. > i am needing to pull out a value that is in parenthesis right after a > certain word, > like the first time the word 'foo' is found, retrieve the values in the > next set of parenthesis (bar) and it would return 'bar' > > i think i can use re to do this, but is there some easier way? > thanks > Using string methods to locate the 'foo' instances is by far the fastest way to go.
If your requirements get more complicated, look into using pyparsing (http://pyparsing.sourceforge.net). Here is a pyparsing rendition of this problem. This does three scans through some sample data - the first lists all matches, the second ignores matches if they are found inside a quoted string, and the third reports only the third match. This kind of context-sensitive matching gets trickier with basic string and re tools. -- Paul data = """ i have a text file with a bunch of foo(bar1) values scattered throughout it. i am needing to pull out a value that foo(bar2) is in parenthesis right after a certain word, like the foo(bar3) first time the word 'foo' is found, retrieve the values in the next set of parenthesis foo(bar4) and it would return 'bar' do we want to skip things in quotes, such as 'foo(barInQuotes)'? """ from pyparsing import Literal,SkipTo,quotedString pattern = Literal("foo") + "(" + SkipTo(")").setResultsName("payload") + ")" # report all occurrences of xxx found in "foo(xxx)" for tokens,start,end in pattern.scanString(data): print tokens.payload, "at location", start print # ignore quoted strings pattern.ignore(quotedString) for tokens,start,end in pattern.scanString(data): print tokens.payload, "at location", start print # only report 3rd occurrence tokenMatch = {'foo':0} def thirdTimeOnly(strg,loc,tokens): word = tokens[0] if word in tokenMatch: tokenMatch[word] += 1 if tokenMatch[word] != 3: raise ParseException(strg,loc,"wrong occurrence of token") pattern.setParseAction(thirdTimeOnly) for tokens,start,end in pattern.scanString(data): print tokens.payload, "at location", start print Prints: bar1 at location 36 bar2 at location 116 bar3 at location 181 bar4 at location 278 barInQuotes at location 360 bar1 at location 36 bar2 at location 116 bar3 at location 181 bar4 at location 278 bar3 at location 181 -- http://mail.python.org/mailman/listinfo/python-list
