Key value pairs in dictionary, and how to retrieve them given one?

[nvadithya]

I'm wondering on how to retrieve the key given the value of a dictionary?

The way to get value given the key is

array[key] - this will output the value, but what if I have the value and am looking to get the key?

[iodwyer · Accepted solution]

q)d:`a`b`c!1 2 3
q)d[`a]
1
q)d?1
`a
q)d:`a`b`c`d!1 2 3 1
q)d?1
`a

be mindful, with this method and duplicate values, only the first key is returned 

[nvadithya]

This is exactly, what I've been looking for, thank you!

[BaiChen]

you also can use where clause, which return all keys that have duplicates:

q)dic:`a`b`c`d!1 2 3 1
q)where dic=1
q)`a`d
q)