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Top Forums Shell Programming and Scripting Awk, function of underscore char. Post 302888248 by EAGL€ on Thursday 13th of February 2014 12:03:08 PM
Old 02-13-2014
Quote:
Originally Posted by Scrutinizer
It sets an array element with index $0 to the value 1. In the second part, if checks if for $4 in the second file there is an array element with a value other than 0 or "" and if so, it does not print the record.

Another (slightly better) way of doing it would be:
Code:
awk -F, 'NR==FNR{A[$0]; next}!($4 in A)' exclude infile

this way is really more clear, understandable for me Scrutinizer, thanks!

Corona so its a lazy (or shorter) way of using variables Smilie
 

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unset(n)						       Tcl Built-In Commands							  unset(n)

__________________________________________________________________________________________________________________________________________________

NAME
unset - Delete variables SYNOPSIS
unset ?-nocomplain? ?--? ?name name name ...? _________________________________________________________________ DESCRIPTION
This command removes one or more variables. Each name is a variable name, specified in any of the ways acceptable to the set command. If a name refers to an element of an array then that element is removed without affecting the rest of the array. If a name consists of an array name with no parenthesized index, then the entire array is deleted. The unset command returns an empty string as result. If -nocom- plain is specified as the first argument, any possible errors are suppressed. The option may not be abbreviated, in order to disambiguate it from possible variable names. The option -- indicates the end of the options, and should be used if you wish to remove a variable with the same name as any of the options. If an error occurs, any variables after the named one causing the error not deleted. An error can occur when the named variable does not exist, or the name refers to an array element but the variable is a scalar, or the name refers to a variable in a non-existent namespace. EXAMPLE
Create an array containing a mapping from some numbers to their squares and remove the array elements for non-prime numbers: array set squares { 1 1 6 36 2 4 7 49 3 9 8 64 4 16 9 81 5 25 10 100 } puts "The squares are:" parray squares unset squares(1) squares(4) squares(6) unset squares(8) squares(9) squares(10) puts "The prime squares are:" parray squares SEE ALSO
set(n), trace(n), upvar(n) KEYWORDS
remove, variable Tcl 8.4 unset(n)
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