CODEWITHSUNDEEP
arraystclsorting
Puneet Mittal
Puneet Mittal

Reputation: 542

Sort a tcl array and get the array key.

Hi i have an array with basic key-value pair and i want to sort it and then get the keys. The array contents are something like this:

arrVal {
    123adf45ad    ABCD.1
    aldfhr435d    ABCD.9
    lkh45q9er4    ABCD
    1234dartf4    ABCD4
}

So basically my array keys are some kind of encrypted ids and the values are a string values. Since i cannot sort array based on its keys i did something like this:

foreach {key in array..} {
    lappend mylist [$arrVal($key)]; 
}
set mylist [lsort $mylist];

now for the sorted list i want to extract the array keys against those values. I couldn't find any command that can extract the array keys based on its values. Any help?

Upvotes: 2

Views: 9536

Answers (3)

glenn jackman
glenn jackman

Reputation: 246877

Here's a more step-by-step method:

array set arrVal {
    123adf45ad    ABCD.1
    aldfhr435d    ABCD.9
    lkh45q9er4    ABCD
    1234dartf4    ABCD4
}
set arrValList [list]
foreach {key val} [array get arrVal] {lappend arrValList [list $key $val]}
set sortedKeys [list]
foreach pair [lsort -index 1 $arrValList] {lappend sortedKeys [lindex $pair 0]}
puts $sortedKeys  ;# lkh45q9er4 123adf45ad aldfhr435d 1234dartf4

Upvotes: 1

potrzebie
potrzebie

Reputation: 1798

You can get a list of all the keys in an array with array names.

set mylist [lsort [array names arrVal]]

Upvotes: 0

slebetman
slebetman

Reputation: 113926

Basically you're almost there. What you want is a reverse map which is not something built into the language (or indeed most languages) but rather a concept: another array with the values of the first array as keys and keys of the first array as values:

array set reverseMap {}
foreach {key val} [array get arrayVal] {
    set reverseMap($val) $key
}

Now you can get the keys like this:

set secondKey $reverseMap([lindex $mylist 1])

Upvotes: 3

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