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Swap key-value in dictionary

powerpeanuts
New Contributor III

hi, how can I swap key and list of values using q? Thanks!

python version: https://stackoverflow.com/questions/51740270/python-dictionary-swap-keyvalue-pair-when-values-exist-...

 

for example:

1 2 3!(4 5 3;6 7 3;4 1)

becomes

1 3 4 5 6 7!(enlist 3;1 2;1 3;enlist 1;enlist 2;enlist 2)

1 ACCEPTED SOLUTION

cillianreilly
New Contributor II

This achieves what you're looking for.

q)d:1 2 3!(4 5 3;6 7 3;4 1)
q)r:1 3 4 5 6 7!(enlist 3;1 2;1 3;enlist 1;enlist 2;enlist 2)
q){a!key[x]where each flip value(a:asc distinct raze x)in/:x} d
1| ,3
3| 1 2
4| 1 3
5| ,1
6| ,2
7| ,2
q)r~{a!key[x]where each flip value(a:asc distinct raze x)in/:x}d
1b

View solution in original post

3 REPLIES 3

cillianreilly
New Contributor II

This achieves what you're looking for.

q)d:1 2 3!(4 5 3;6 7 3;4 1)
q)r:1 3 4 5 6 7!(enlist 3;1 2;1 3;enlist 1;enlist 2;enlist 2)
q){a!key[x]where each flip value(a:asc distinct raze x)in/:x} d
1| ,3
3| 1 2
4| 1 3
5| ,1
6| ,2
7| ,2
q)r~{a!key[x]where each flip value(a:asc distinct raze x)in/:x}d
1b

Another method:

 

q){a!x a:asc key x:group(!). flip raze key[x],''value x}d
1| ,3
3| 1 2
4| 1 3
5| ,1
6| ,2
7| ,2

 

 

Rolf
New Contributor III
{key[x][i]!get[x]i:iasc key x:group(!). flip raze key[x],''get x}

indexing into the keys instead of doing a lookup a smidge faster