[python] Python Dictionary contains List as Value - How to update?

I have a dictionary which has value as a list.

dictionary = { 
               'C1' : [10,20,30] 
               'C2' : [20,30,40]
             }

Let's say I want to increment all the values in list of C1 by 10, how do I do it?

dictionary.get('C1') gives me the list but how do i update it?

This question is related to python list dictionary

The answer is


An accessed dictionary value (a list in this case) is the original value, separate from the dictionary which is used to access it. You would increment the values in the list the same way whether it's in a dictionary or not:

l = dictionary.get('C1')
for i in range(len(l)):
    l[i] += 10

for i,j in dictionary .items():
    if i=='C1':
        c=[]
        for k in j:
            j=k+10
            c.append(j)
            dictionary .update({i:c})

dictionary["C1"]=map(lambda x:x+10,dictionary["C1"]) 

Should do it...


Probably something like this:

original_list = dictionary.get('C1')
new_list = []
for item in original_list:
  new_list.append(item+10)
dictionary['C1'] = new_list

why not just skip .get altogether and do something like this?:

for x in range(len(dictionary["C1"]))
    dictionary["C1"][x] += 10

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