getting a key for a given value in the dict

[psbasha]

Hi,

I would like to get a key for a given value in the dict.For example:

I/P:

Sample
dict1 = { 100:[10001,10002,10006,10009,10008],200:[100010,100020,100023],300:[100030,100031,1000041]}
 

Assume that the Keys and Values are unique in the above scenario.

I would like to search the respective key for the given value "100020".

O/P :
200

Is there any simple way,where I can search the 'key' for a given 'value',without using the "for" loop.

If any method available then it will save the time from searching in a bigger dictionary data


Thanks
PSB

[bvdet]

Hi,

I would like to get a key for a given value in the dict.For example:

I/P:

Sample
dict1 = { 100:[10001,10002,10006,10009,10008],200:[100010,100020,100023],300:[100030,100031,1000041]}
 

Assume that the Keys and Values are unique in the above scenario.

I would like to search the respective key for the given value "100020".

O/P :
200

Is there any simple way,where I can search the 'key' for a given 'value',without using the "for" loop.

If any method available then it will save the time from searching in a bigger dictionary data


Thanks
PSB

The for loop is the simplest way I know of.

# Search in dict.values() for specific value, return key
 
dd = {100:[10001,10002,10006,10009,10008],200:[100010,100020,100023],300:[100030,100031,1000041]}
target = 100020
 
for key in dd:
    if target in dd[key]:
        break
 
print key

If there is a more efficient way, I would like to hear about it also!

[bartonc]

Search TheScripts for "inverse dictionary" and you'll see that this is a very common practice.

[ghostdog74]

this is the usual way. however you could always create a function once, then use it whenever you need to find something in a dictionary. Just pass in the dictionary and the search target to that function or something like that.