I avoided associative arrays in my suggestion, because I only have access to bash version 3.2.57(1)-release (x86_64-apple-darwin16) and it doesn't have associative arrays. The bash man page has long had the following bug listed: "It's too big and too slow" (at the very bottom of the man page). Bash provides one-dimensional indexed and associative array variables. If you agree with that, then you probably won't want to read about the "new" associative arrays that were added in version 4.0 of bash. Using unset() Function: The unset() function is used to remove element from the array. Unfortunately, bash and ksh declare associative arrays They work quite similar as in python (and other languages, of course with fewer features :)). Example Function: Alternately, only increment the counter in the conditional code for when you dont remove and item. There are the associative arrays and integer-indexed arrays. To access array elements, we use array_name[index] format. @Michael: Crap, you're right. I even checked older bash and it's still wrong there; like you say set -x shows how it expands. unset array[0] removes the element but still if I do echo ${array[0]} I get a null value moreover there are other ways of doing this but if an element of an array contains spaces like below array[0]='james young' array[1]='mary' array[2]='randy orton' but these also fail to do the job. Similarly, we can use delete statement to remove an element from the array. I normally use ksh instead of bash (and it has had associative arrays since 1993). The syntax of delete statement is as follows − Syntax delete array_name[index] The following example deletes the element orange. Dictionary / associative arrays / hash map are very useful data structures and they can be created in bash. Create a temporary associative array. Deleting an element from the array To delete an element from the array we need to know it's index or its key in the case of an associative array, and use the unset command. So "if condition then incremement counter, else remove item at current position" Last edited by Trilby (2012-09-06 11:51:32) This allows us to effectively remove array duplicates. I have no idea why you have two counters. CAVEAT: Requires bash 4+ CAVEAT: List order may not stay the same. on April 28, 2010. Deleting Array Elements. Elements in arrays are frequently referred to by their index number, which is the position in which they reside in the array. This unset command takes the array key as input and removed that element from the array. dictionaries were added in bash version 4.0 and above. I guess I didn't test that comment before posting. For insertion, we used assignment operator. We will go over a few examples. Let's see an example: Bash Associative Arrays by Mitch Frazier. The unset function is used to destroy any other variable and same way use to delete any element of an array. 6.7 Arrays. These index numbers are always integer numbers which start at 0. It only works with a 1-element array of an empty string, not 2 elements. Bash, however, includes the ability to create associative arrays, and it treats these arrays the same as any other array. Any variable may be used as an indexed array; the declare builtin will explicitly declare an array. An associative array lets you create lists of key and value pairs, instead of just numbered values. Arrays in Bash. To check the version of bash run following: Remove duplicate array elements. When setting associative array values and a duplicate assignment occurs, bash overwrites the key. When you remove one from the array, you should decrement the counter. Introduction to bash arrays and bash array operations. 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