unconditional patterns into if/else 
Author Message
 unconditional patterns into if/else

Quote:


> > How do I turn a set of patterns into IF/ELSE?
> > Right now, the script below works fine.

> > /DTYY$/    ||   \
> > /DTYK$/    ||   \
> > /DTPK/     ||   \
> > {print FILENAME "\t" $0}

> [...]

> #2 If you have a newer awk - nawk, mawk, gawk, tawk or HP-UX awk,
>    then you can combine and simplify those patterns:

>       /DT(Y(Y|K)$|PK)/

>    If you examine that closely you should be able to understand it.

I suspect the pattern /DTPK/ instead of /DTPK$/ was a typo, in which
case this

     /DT(Y(Y|K)$|PK)/

can be expressed like this

     /DT(Y[YK]|PK)$/

or like this

     /DT(YY|[YP]K)$/

Just my $.02 worth...

--
Jim Monty

http://www.*-*-*.com/ ~monty/
Tempe, Arizona USA



Sun, 21 Oct 2001 03:00:00 GMT  
 unconditional patterns into if/else

Quote:

>So I tried:

># comment
>if ( /DTYY$/    ||   \
>/DTYK$/    ||   \
>/DTPK/     ||   )

>{print FILENAME "\t" $0}

># end
>----------------------

>But I never got to the "else".
>When I tested this half, awk bailed out, at "if".
>So, what am I missing?

The if is an action thing and must be within the curly brace part,
not in the pattern part.

awk '{if( $0 ~ /DTYY$/ || $0 ~ /DTYK$/ || $0 ~ /DTPK/){
      print FILENAME "\t" $0} else {print "Error\t" $0}}' infile

but since you want to print something in either case, try using the ? :
construct (assuming your awk supports it):

gawk '{print ( ( $0 ~ /DTYY$/ || $0 ~ /DTYK$/ || $0 ~ /DTPK/) \
      ? FILENAME "\t" : "Error\t" ) $0}' infile

For this infile:

DTYK
DTYKa
DTYY
DTYYa
DTPK
DTPKa
DOTY

it produced this (as did the other script I wrote above):

infile  DTYK
Error   DTYKa
infile  DTYY
Error   DTYYa
infile  DTPK
infile  DTPKa
Error   DOTY

You could also tidy up the regular expression, as others have posted.

Chuck Demas
Needham, Mass.

--
  Eat Healthy    |   _ _   | Nothing would be done at all,

  Die Anyway     |    v    | That no one could find fault with it.



Mon, 22 Oct 2001 03:00:00 GMT  
 unconditional patterns into if/else

Quote:
>What I want to add is, if the patterns are NOT present, then output a message.

Assuming what you posted is your entire script,  you can achieve this
by changing the first action to:

    {print FILENAME "\t" $0; next}

and adding an unconditional action after it:

    { print "error message goes here" }

This gives you two actions:  one that gets executed on a match,  and one
that's executed when the match fails.  This is not exactly a
"general-purpose" practice, since you can only use it once per program,
but sometimes one is all you need  ;-)

Ran



Mon, 22 Oct 2001 03:00:00 GMT  
 
 [ 6 post ] 

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