CODEWITHSUNDEEP
pythonlistdictionary
MrRaken
MrRaken

Reputation: 35

how to modify a list that is a value in a dictionary?

If I have a dictionary like so:

d = {'USA' : [0,0,0], 'CAN' : [0,0,0]}

How can I update a specific element in the value?

My goal is to update it to look like (for example) this:

d = {'USA' : [0,1,0], 'CAN' : [1,0,0]}

I was thinking something like

d['USA'] = d.get('USA')[1] +  1

d['CAN'] = d.get('CAN')[0] +  1

but this doesn't seem to work. Any suggestions? I hope this is clear.

Upvotes: 1

Views: 82

Answers (3)

Bear
Bear

Reputation: 516

The simplest way would be to just say

d['USA'][1] += 1

That will get you the updated list.

Upvotes: 1

Manishearth
Manishearth

Reputation: 16188

Do

d['USA'][1]=d['USA'][1]+1
d['CAN'][0]=d['USA'][0]+1

In your example you were replacing the whole list with a single number.

Upvotes: 0

Martijn Pieters
Martijn Pieters

Reputation: 1121446

You have lists inside of your dictionary, so the d[key] part of the expression returns a list. Just keep adding [..] indexings:

d['USA'][1] += 1
d['CAN'][0] += 1

You could break it down with intermediary variables if that is easier:

sublist = d['USA']
sublist[1] += 1
sublist = d['CAN']
sublist[0] += 1

Upvotes: 4

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