tc90 tc90 - 1 year ago 104
Bash Question

How can i delete an element in an array and then shift the array in Shell Script?

First let me state my problem clearly:

Ex: Let's pretend this is my array, (the elements don't matter as in my actual code they vary):

array=(jim 0 26 chris billy 78 hello foo bar)

Now say I want to remove the following elements:

chris 78 hello

So I did:
unset array[$i]
while looping through the array.
This removes the elements correctly, however, i end up with an array that looks like this:

array=(jim 0 26 '' billy '' '' foo bar)

I need it to look like this:

array=(jim 0 26 billy foo bar)

where jim is at index 0, 0@1, 26@2, etc..

How do I delete the elements in the array and move the other elements so that there are no null/empty spaces in the array?


Answer Source

Try this:

$ array=( "one two" "three four" "five six" )
$ unset array[1]
$ array=( "${array[@]}" )
$ echo ${array[0]}
one two
$ echo ${array[1]}
five six

Shell arrays aren't really intended as data structures that you can add and remove items from (they are mainly intended to provide a second level of quoting for situations like

arr=( "one two" "three four" )
somecommand "${arr[@]}"

to provide somecommand with two, not four, arguments). But this should work in most situations.

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