Can Python dictionaries to be as handy as PHP array?

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?

Why wouldn't you use the actual OOP features of Python instead? This question just sounds a bit trollish. — aychedee, Jul 03 '12 at 22:32

score 4 · Accepted Answer · answered Jul 03 '12 at 22:36

4

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!)

answered Jul 03 '12 at 22:36

Hugh Bothwell

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ImportError: cannot import name Counter. Any idea? – Cheng-Lin Yang Jul 03 '12 at 22:44
1

@Cheng-Lin Yang: are you using a version of Python prior to 2.7? If so, I recommend http://code.activestate.com/recipes/576611/ as a replacement. – Hugh Bothwell Jul 03 '12 at 22:46

score 2 · Answer 2 · edited May 23 '17 at 12:20

2

You can use Python's defaultdict (as this answer suggests):

from collections import defaultdict
user = "Tom"
type = "New"
userlist = defaultdict(lambda: defaultdict(int))
userlist[user]['count'] += 1
userlist[user][type] += 1

edited May 23 '17 at 12:20

Community

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answered Jul 03 '12 at 22:31

dusan

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Can Python dictionaries to be as handy as PHP array?

2 Answers2