Concatenate values in python dictionary

Question

I have a python dictionary and I'd like to concatenate the values of value[0] and a list in value [1]

so

dict={       'Key1':['MASTER',['_A','_B','_C']]}

and expected output is of calling Key1 is

[['MASTER_A','MASTER_B','MASTER_C']]

Answer 1

Use a nested comprehension:

d = {'Key1':['MASTER',['_A','_B','_C']]}
result_dict = {k: [v[0] + l for l in v[1]] for k,v in d.items()}

For example:

>>> result_dict = {k: [v[0] + l for l in v[1]] for k,v in d.items()}
>>> result_dict
{'Key1': ['MASTER_A', 'MASTER_B', 'MASTER_C']}

Answer 2

Try this :

d = {'Key1':['MASTER',['_A','_B','_C']]}
out = [d['Key1'][0]+i for i in d['Key1'][1]]

Output :

['MASTER_A', 'MASTER_B', 'MASTER_C']

To assign it to the key, do :

d['Key1'] = out