Question

Recently, I’m working on a Python-based project and facing a issue with dictionaries. In PHP I can easily create a multiple dimension array by the following instruction:

$user = "Tom";
$type = "New";
$userlist[$user]['count'] += 1;
$userlist[$user][$type] += 1;

PHP will create a new element within an array if it doesn’t exist, which is very convenient for coding. Can Python dictionaries provide the same and handy function as PHP?

Answer 1

Python does not magically instantiate dictionaries as PHP does; however, with a bit of forethought, you can make it do what you want.

from collections import defaultdict, Counter

users = defaultdict(Counter)

users['Tom']['Count'] += 1
users['Tom']['New'] += 1

(also, calling a variable “somethinglist” when it’s not a list is probably a bad idea, and type is a Python keyword, so don’t use it as a variable name either!)