Question

drug_input=['MORPHINE','CODEINE']    
def some_function(drug_input)      
      generic_drugs_mapping={'MORPHINE':0,
                                'something':1,
                                'OXYCODONE':2,
                                'OXYMORPHONE':3,
                                'METHADONE':4,
                                'BUPRENORPHINE':5,
                                'HYDROMORPHONE':6,
                                'CODEINE':7,
                                'HYDROCODONE':8}

row is a list.

I would like to set all the members of row[..]='' EXCEPT for those that drug_input defines, in this case it is 0, and 7.

So row[1,2,3,4,5,6,8]=''

If row is initially:

row[0]='blah'
row[1]='bla1'
...
...
row[8]='bla8'

I need:

row[0]='blah' (same as before)
row[1]=''
row[2]=''
row[3]=''
...
...
row[7]='bla7'
row[8]=''

How do I do this?

Answer 1

You could first create a set of all the indexes that should be kept, and then set all the other ones to '':

keep = set(generic_drugs_mapping[drug] for drug in drug_input)
for i in range(len(row)):
  if i not in keep:
    row[i] = ''