Sponsored Content
Top Forums Shell Programming and Scripting Using unset to delete array elements Post 302250079 by msb65 on Wednesday 22nd of October 2008 04:47:23 PM
Old 10-22-2008
Hi Jim,

I really appreciate your help! Two final questions:

- When you use unset, you refer to the array with "$" and "{}". When I use them I get an error:
michael-browns-powerbook-g4-15:~ msb65$ array=(1 2 3 4)
michael-browns-powerbook-g4-15:~ msb65$ unset ${array[1]}
-bash: unset: `2': not a valid identifier

The only way I get it work is if I type:
michael-browns-powerbook-g4-15:~ msb65$ unset array[1]

Why is that?. What is the difference between the two methods?

- Is there any way to just eliminate an array element (ie reorder the array)?

Mike
 

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

PHP: how can I delete empty/NULL elements from a multi-dimensional array.

Hi all I have a file that i'm running and exec(cat ./dat) against..and putting its contents into any array, then doing an exploding the array into a multi-dimension array... The 15 multi-dimensional arrays have elements that are null/empty, I would like to remove/unset these elements and then... (2 Replies)
Discussion started by: zeekblack
2 Replies

2. Shell Programming and Scripting

Array with String Elements

How can I get my array to understand the double-quotes I'm passing into it are to separate text strings and not part of an element? here's what I'm working with... db2 -v connect to foo db2 -x "select '\"' || stats_command || '\",' from db2law1.parallel_runstats where tabname = 'BAZ'" set... (4 Replies)
Discussion started by: djschmitt
4 Replies

3. UNIX for Dummies Questions & Answers

Help with replacing Array elements

Hi, I have an array containing following sample information @array = qw (chr02 chr02 chr02 chr02 chr02 chr03 chr03 chr04 chr04 chr05 chr05 chr05 chr07 chr07) I need to replace all duplicate entries by an underscore to get the following output@array = qw (chr02 _ _ _ _ chr03 _ chr04 _ chr05 _ _... (4 Replies)
Discussion started by: pawannoel
4 Replies

4. UNIX for Dummies Questions & Answers

printing array elements

Is there a way to print multiple array elements without iterating through the array using bash? Can you do something like... echo ${array}and get all those separate elements from the array? (2 Replies)
Discussion started by: jrymer
2 Replies

5. Shell Programming and Scripting

Grouping array elements - possible?

I have a script which takes backup of some configuration files on my server. It does that by using an array which contains the complete path to the files to backup. It copys the files to a pre defined dir. Each "program" has it's own folder, ex. apache.conf is being copied to /predefined... (7 Replies)
Discussion started by: dnn
7 Replies

6. Programming

Array Elements Check

Hi everyone, :) I'm trying to make a simple C program that scans an array of chars to see if its elements are similar. I can't understand what's wrong. Could you help me to fix this? Here is the code. Thanks! #include<stdio.h> int main() { int arr; int i, len; int flag =... (10 Replies)
Discussion started by: IgorGest
10 Replies

7. Shell Programming and Scripting

Random elements from array

Hi I wanted to print random elements from an array at bash shell I use the following code, but I always see first element getting printed #!/bin/bash c=1 expressions=(pink red white yellow purple) while ]; do echo "The value of RANDOM is $RANDOM" selectedexpression=${expressions}]};... (5 Replies)
Discussion started by: Priya Amaresh
5 Replies

8. Shell Programming and Scripting

Help reading the array and sum of the array elements

Hi All, need help with reading the array and sum of the array elements. given an array of integers of size N . You need to print the sum of the elements in the array, keeping in mind that some of those integers may be quite large. Input Format The first line of the input consists of an... (1 Reply)
Discussion started by: nishantrefound
1 Replies

9. UNIX for Beginners Questions & Answers

Unset array element and save to file in Bash

#!/bin/bash X=(2H 4S 10D QC JD 9H 8S) How do I unset the 10D from this array and save it to a file? Please use CODE tags as required by forum rules! (5 Replies)
Discussion started by: cogiz
5 Replies

10. Shell Programming and Scripting

Get unique elements from Array

I have an array code and output is below: echo $1 while read -r fline; do echo "%%%%%%$fline%%%%%" fmy_array+=("$fline") done <<< "$1" Output: CR30903 YU0007 SRIL CR30903 Yogesh SRIL %%%%%%CR30903 YU0007 SRIL%%%%% %%%%%%CR30903 Yogesh SRIL%%%%% ... (8 Replies)
Discussion started by: mohtashims
8 Replies
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 are 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)
All times are GMT -4. The time now is 03:48 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy