# Print last occurrence if first field match **URL:** \ **Category:** Shell Programming and Scripting\ **Created:** [November 15, 2007, 9:30am UTC](https://community.unix.com/t/print-last-occurrence-if-first-field-match/177807 "2007-11-15T09:30:44Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![Raynon](https://community.unix.com/letter_avatar/raynon/32/5_5575768a8748004e209b776fc1b2916d.png) [@Raynon](https://community.unix.com/u/Raynon)\ **Post date:** [November 15, 2007, 9:30am UTC](https://community.unix.com/t/print-last-occurrence-if-first-field-match/177807/1 "2007-11-15T09:30:44Z")
Hi All, I have an input below. If the term in the 1st column is equal, print the last row which 1st column is equal.In the below example, it's " 0001 k= 27 " and " 0004 k= 6 " (depicted in bold). Those terms in 1st column which are not repetitive are to be printed as well. Can any body help me by using awk or perl ? Thanks Input: 0001 k= 1 0001 k= 26 0001 k= 27 0002 k= 1 0003 k= 1 0004 k= 1 0004 k= 4 0004 k= 5 0004 k= 6 Output: 0001 k= 27 0002 k= 1 0003 k= 1 0004 k= 6 ---
**Author:** ![vgersh99](https://community.unix.com/user_avatar/community.unix.com/vgersh99/32/14851_2.png) [@vgersh99](https://community.unix.com/u/vgersh99)\ **Post date:** [November 15, 2007, 9:50am UTC](https://community.unix.com/t/print-last-occurrence-if-first-field-match/177807/2 "2007-11-15T09:50:23Z")
assuming your input is sorted based on the first column... nawk -f ray.awk myInputFile ray.awk: ```nohighlight # if the value in the first column ($1) does not equal the value stored in "prevIDX" # and we are not at the FIRST record (FNR != 1) [FNR = RecordNumber in the current File]- print the value of "prev" $1 != prevIDX && FNR != 1 { print prev} # assign the value of the FIRST field ($1) to a variable "prevIDX" # assign the entire record/line to the variable "prev" { prevIDX=$1; prev=$0 } # after ALL the records/lines were processed - print the value of the variable "prev" # the last/dangling record/line END { print prev } ``` ---
**Author:** ![Raynon](https://community.unix.com/letter_avatar/raynon/32/5_5575768a8748004e209b776fc1b2916d.png) [@Raynon](https://community.unix.com/u/Raynon)\ **Post date:** [November 15, 2007, 10:05am UTC](https://community.unix.com/t/print-last-occurrence-if-first-field-match/177807/3 "2007-11-15T10:05:40Z")
> [@vgersh99](#): > > assuming your input is sorted based on the first column... > > nawk -f ray.awk myInputFile > > ray.awk: > > ```plaintext > $1 != prevIDX && FNR != 1 { print prev} > { prevIDX=$1; prev=$0 } > END { print prev } > > ``` Hi vgersh99, That's cool!! It works!! You a are brillant!! But i ' m new to the " prev " and " FNR " term. Can you explain your code so that i can understand better ? ---
**Author:** ![vgersh99](https://community.unix.com/user_avatar/community.unix.com/vgersh99/32/14851_2.png) [@vgersh99](https://community.unix.com/u/vgersh99)\ **Post date:** [November 15, 2007, 10:17am UTC](https://community.unix.com/t/print-last-occurrence-if-first-field-match/177807/4 "2007-11-15T10:17:52Z")
see the comments in the original post. ---
**Author:** ![Raynon](https://community.unix.com/letter_avatar/raynon/32/5_5575768a8748004e209b776fc1b2916d.png) [@Raynon](https://community.unix.com/u/Raynon)\ **Post date:** [November 16, 2007, 3:07am UTC](https://community.unix.com/t/print-last-occurrence-if-first-field-match/177807/5 "2007-11-16T03:07:38Z")
Hi vgersh99, Can i use " NR " instead of " FNR " for this case this there's only one input file ? ---
**Author:** ![vgersh99](https://community.unix.com/user_avatar/community.unix.com/vgersh99/32/14851_2.png) [@vgersh99](https://community.unix.com/u/vgersh99)\ **Post date:** [November 16, 2007, 8:41am UTC](https://community.unix.com/t/print-last-occurrence-if-first-field-match/177807/6 "2007-11-16T08:41:09Z")
> [@raynon](#): > > Hi vgersh99, > > Can i use " NR " instead of " FNR " for this case this there's only one input file ? don't see why not..... ---
**Author:** ![Raynon](https://community.unix.com/letter_avatar/raynon/32/5_5575768a8748004e209b776fc1b2916d.png) [@Raynon](https://community.unix.com/u/Raynon)\ **Post date:** [November 16, 2007, 8:59am UTC](https://community.unix.com/t/print-last-occurrence-if-first-field-match/177807/7 "2007-11-16T08:59:38Z")
Thanks vgersh99!! 😃 Thanks for your guidance! ---
**Author:** ![summer\_cherry](https://community.unix.com/letter_avatar/summer_cherry/32/5_5575768a8748004e209b776fc1b2916d.png) [@summer\_cherry](https://community.unix.com/u/summer_cherry)\ **Post date:** [November 18, 2007, 9:49pm UTC](https://community.unix.com/t/print-last-occurrence-if-first-field-match/177807/8 "2007-11-18T21:49:17Z")
HI, code: ```nohighlight awk ' { out[$1]=$0 } END{ for (i in out) print out }' filename ``` ---
**Author:** ![Raynon](https://community.unix.com/letter_avatar/raynon/32/5_5575768a8748004e209b776fc1b2916d.png) [@Raynon](https://community.unix.com/u/Raynon)\ **Post date:** [November 19, 2007, 8:40am UTC](https://community.unix.com/t/print-last-occurrence-if-first-field-match/177807/9 "2007-11-19T08:40:20Z")
> [@summer\_cherry](#): > > HI, > > code: > > ```plaintext > awk ' > { > out[$1]=$0 > } > END{ > for (i in out) > print out > }' filename > > ``` Hi Summer, Your code is able to work but some how the sequence of display seems to be jumbled up. " 0004 " should be at the last line but it came to the 1st line. Below is my output using your code: $ awk -f myawk data 0004 k= 6 0001 k= 27 0002 k= 1 0003 k= 1 ---
**Author:** ![Raynon](https://community.unix.com/letter_avatar/raynon/32/5_5575768a8748004e209b776fc1b2916d.png) [@Raynon](https://community.unix.com/u/Raynon)\ **Post date:** [March 13, 2008, 3:28am UTC](https://community.unix.com/t/print-last-occurrence-if-first-field-match/177807/10 "2008-03-13T03:28:20Z")
Hi vgersh99, If i need to capture the 1st occurrence instead that is if column1 of row1 equals to column1 of row2 then the whole line of column1 row1 is being printed out , how can i modify your code below to fulfill this requirement? ```nohighlight $1 != prevIDX && FNR != 1 { print prev} { prevIDX=$1; prev=$0 } END { print prev } ``` Input: 0001 k= 1 0001 k= 26 0001 k= 27 0002 k= 1 0003 k= 1 0004 k= 1 0004 k= 4 0004 k= 5 0004 k= 6 Output: 0001 k= 1 0002 k= 1 0003 k= 1 0004 k= 1