Sponsored Content
Top Forums Shell Programming and Scripting Displaying the first field if the second field matches the pattern using Perl Post 302727205 by elixir_sinari on Tuesday 6th of November 2012 02:12:51 AM
Old 11-06-2012
Quote:
Originally Posted by royalibrahim
I Just want to understand whether in Perl, is it possible to iterate over a file object using a for loop as I did in my code? Perl complains no error even if you use it.
Of course, yes. You did it, right?

Why would perl complain when what you were doing was syntactically correct but logically wrong?

Never use a for (or foreach) loop to read a file. In this case, all lines from the file (depending on the input record separator) will be read in at once and stored in memory to form a list. Your loop will then iterate over the elements of this list. So, you might hit your system's memory limits.

A while loop is much much better as it reads one record at a time.
This User Gave Thanks to elixir_sinari For This Post:
 

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Print line if first Field matches a pattern

Hi All, I would like my code to be able to print out the whole line if 1st field has a dot in the number. Sample input and expected output given below. My AWK code is below but it can;t work, can any expert help me ? Thanks in advance. {if ($1 ~ /*\.*/) { print $0 }} Input: ... (2 Replies)
Discussion started by: Raynon
2 Replies

2. Shell Programming and Scripting

Displaying lines of a file where the second field matches a pattern

Howdy. I know this is most likely possible using sed or awk or grep, most likely a combination of them together, but how would one go about running a grep like command on a file where you only try to match your pattern to the second field in a line, space delimited? Example: You are... (3 Replies)
Discussion started by: LordJezoX
3 Replies

3. Shell Programming and Scripting

adding field values if field matches

hi i have file as below , i want to add duplicate records like bell_bb to one record with valuve as 15 ( addition of both ) any oneline awk script to achive this ? header 0 CAMPAIGN_NAME 1 Bell_BB 14 Bell_MONTHLY 803 SOLO_UNBEATABLE 644 Bell_BB 1 Bell_MONTHLY 25 SOLO_UNBEATABLE... (4 Replies)
Discussion started by: raghavendra.cse
4 Replies

4. Shell Programming and Scripting

How to print line if field matches?

Hi all, I got several lines line this a b c d e 1 e a 1 c d e 3 f a b c 1 e 8 h a b c d e 1 w a 1 c d e 2 w a b c d e 1 t a b c d e 7 4 How can I print the line if 1 is the field one before the last field? Basicly this 2 field ? a b c d e 1 e a b c d e 1 t The file I got is... (7 Replies)
Discussion started by: stinkefisch
7 Replies

5. Shell Programming and Scripting

awk to sum specific field when pattern matches

Trying to sum field #6 when field #2 matches string as follows: Input data: 2010-09-18-20.24.44.206117 UOWEXEC db2bp DB2XYZ hostname 1 2010-09-18-20.24.44.206117 UOWWAIT db2bp DB2XYZ hostname ... (3 Replies)
Discussion started by: ux4me
3 Replies

6. Shell Programming and Scripting

AWK: Pattern match between 2 files, then compare a field in file1 as > or < field in file2

First, thanks for the help in previous posts... couldn't have gotten where I am now without it! So here is what I have, I use AWK to match $1 and $2 as 1 string in file1 to $1 and $2 as 1 string in file2. Now I'm wondering if I can extend this AWK command to incorporate the following: If $1... (4 Replies)
Discussion started by: right_coaster
4 Replies

7. Shell Programming and Scripting

Displaying a field completely

Version: AIX 6.1 (korn shell) In the below output, the field with the heading 'Address' has some names like hwproc214-priv1.gnas.wrd.netwhich are only partially displayed. $ netstat -i Name Mtu Network Address Ipkts Ierrs Opkts Oerrs Coll en2 1500 link#2 ... (3 Replies)
Discussion started by: polavan
3 Replies

8. UNIX for Dummies Questions & Answers

Match pattern in a field, print pattern only instead of the entire field

Hi ! I have a tab-delimited file, file.tab: Column1 Column2 Column3 aaaaaaaaaa bbtomatoesbbbbbb cccccccccc ddddddddd eeeeappleseeeeeeeee ffffffffffffff ggggggggg hhhhhhtomatoeshhh iiiiiiiiiiiiiiii ... (18 Replies)
Discussion started by: lucasvs
18 Replies

9. UNIX for Dummies Questions & Answers

Displaying field of NR, not the line #

Within AWK, how do you display a field of NR? Here's my code: awk '(NR>1) && (P1=$1-w)>=100000 {print "increase of" " " P1*.0000179," " "kW at" " " 'NR*60/431900' " " "minutes" "\n" "change from" " " 'NR-10($1)' " " "kW to" " " 'NR+70($1)' "\n"}{w=$1}' filename I can change NR and print... (3 Replies)
Discussion started by: markymarkg123
3 Replies

10. Shell Programming and Scripting

Need to replace last field in a file,if first field matches

Hi, Need to replace last field in a file(/etc/passwd) ,if first filed matches with particular username. Scenario: cat testfor1 deekshi:x:7082:7082::/home/deekshi:/bin/bash harini1:x:7083:7083::/home/harini1:/bin/bash Here,if first field contains "deekshi", then i should replace... (4 Replies)
Discussion started by: Sumanthsv
4 Replies
Plucene::Search::TermQuery(3pm) 			User Contributed Perl Documentation			   Plucene::Search::TermQuery(3pm)

NAME
Plucene::Search::TermQuery - a query that contains a term SYNOPSIS
# isa Plucene::Search::Query $term_query->normalize($norm); my $ssw = $term_query->sum_squared_weights($searcher); my $as_string = $term_query->as_string($field); DESCRIPTION
A query that matches a document containing a term. Term query are the simplest possible Plucene queries and are used to match a single word. Term queries are represented by instances of the TermQuery class and contain the desired term (word) and a field name, both are case sensitive. The field specified in a Term query must be a document field that was specified as 'indexible' during the indexing process. If the field was specified during indexing as 'tokenized' than the term will be matched against each of tokens (words) found in that field, otherwise, it will be matched against the entire content of that field. A term query may have an optional boost factor (default = 1.0) that allows to increase or decrease the ranking of documents it matches. METHODS
term / idf / weight Get / set these attributes sum_squared_weights my $ssw = $term_query->sum_squared_weights($searcher); This will return the sum squared weights for the passed in searcher. normalize $term_query->normalize($norm); to_string my $as_string = $term_query->as_string($field); perl v5.12.4 2011-08-14 Plucene::Search::TermQuery(3pm)
All times are GMT -4. The time now is 06:36 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy