Re: quick scripting question - finding occurrence in many lines

[Douglas Tutty <dtutty@porchlight.ca>]

On Fri, Nov 03, 2006 at 08:27:42PM +0000, michael wrote:
> I've been trying to do this with 'awk' but am hitting probs (not used
> awk for ages!) so all offers welcome! 
> 
> Given a multiple line file, IN, that contains the word Processor
> (possibly split over 2 lines) I wish to output the field immediately
> preceeding Processor.
> 
> eg for
> 
> junk info 18 Pro
> cessor
> 
> I wish to get the field '18'
> 
> Cheers, Michael
 
I've read the replies telling you about awk and it reminds me why I
never use awk or regular expressions.  My mind doesn't do cryptic.  I
either do fortran77 or python.  For this I would use python so you can
lay it out step by step logically.  

Since it appears that newlines aren't significant, I would get rid of
them. 

	IN = open('IN')
	instring = IN.read()
	IN.close()

I would remove all newlines so it was one huge line. 

	onelinestring = instring.replace('\n', ' ')
	del instring

Split the string into a list of words

	inlist = onelinestring.split()
	del onelinestring

Iterate through the list looking for 'processor'

	oldword = ' '
	for newword in inlist
		if word.lower == 'processor'
			print oldword	# the previous word
		oldword = newword

	del inlist


So I did it in 8 lines instead of one, but in 10 years I'll still know
what those 8 lines do.  All the del lines do is free memory as soon as
possible as there is no need to keep multiple versions of the file
around.  Internally, I don't know how awk and regular expressions handle
this.  

Good luck,

Doug.