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Is this an array?

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# 1  
Old 01-27-2014
Is this an array?
Hi there,

I am currently looking at an existing script that have something like this:

Code:
variable='val1 val2 val3 val4'

Is this another way of setting an array? If not, what is it?

Thank you.
# 2  
Old 01-27-2014
This is a list, which is reckognizable by single or double quotes.
However, an array could look like: array=(val1 val2 val3)

Also you can test yourself by the simple use of echo/printf..
Code:
$ echo $variable
val1 val2 val3 val4

vs.
Code:
$ echo $array
val1
$ echo ${array[@]}
val1 val2 val3

Hope this helps
# 3  
Old 01-27-2014
Not really but it can be used as one if you use something to parse it based on spaces like a "for loop" or "awk"

If it's a korn shell you can use something like:
Code:
set -A variable va1 va2 va3

and then access them using
Code:
 ${variable[0]}
 ${variable[1]}
 ${variable[2]}

ie (remember the first entry in an array is 0).
Code:
set -A cars Ford Chrysler Chevy

would give you:
Code:
print ${cars[1]}
Chrysler

# 4  
Old 01-27-2014
may I ask what is the difference between a list and an array?
# 5  
Old 01-27-2014
Personal preference? When I use a list it is parsed imediately but I'll use an array when I want to save the values for later use. I don't think there's an easy way to reference a specific value in a list further down in your code. (someone is going to jump on this)
This User Gave Thanks to port43 For This Post:
erin00
# 6  
Old 01-28-2014
With arrays you can directly reference specific values by using an index. With a list you can't do that. For example.
Code:
arr=(val1 val2 val3 val4)

To get the third value you use:
Code:
echo "${arr[2]}"

Also to enumerate a list, it is subject to field splitting, whereas an array is not..

For example:
Code:
$ arr=(val1 "val2 and val2b" val3 val4)
$ echo "${arr[1]}"
val2 and val2b

Code:
$ for i in "${arr[@]}"; do echo "$i"; done
val1
val2 and val2b
val3
val4


Code:
$ list='val1 "val2 and val2b" val3 val4' 
$ for i in $list; do echo "$i"; done
val1
"val2
and
val2b"
val3
val4

Last edited by Scrutinizer; 01-28-2014 at 03:39 AM..
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