Comments on: Simple Multi-Dimensional Dictionaries in Python

By: Jonathan

Jonathan — Sat, 07 Nov 2009 07:34:42 +0000

Hi Parand,

Perhaps an example will help,

mydict =
{’WILW1′: {’fx’: ‘8.1′, ‘obtime’: ‘2009-11-07 06:45:00′, ‘ob’: ‘6.9′},
‘GRRW1′: {’fx’: ‘12.8′, ‘obtime’: ‘2009-11-07 04:15:00′, ‘ob’: ‘6.7′},
‘NASW1′: {’fx’: ‘6.8′, ‘obtime’: ‘2009-11-07 06:30:00′, ‘ob’: ‘7.1′}
}

I would like to sort this by the values of the ‘ob’ key. In this case, this would become:

mysorteddic =
{’NASW1′: {’fx’: ‘6.8′, ‘obtime’: ‘2009-11-07 06:30:00′, ‘ob’: ‘7.1′},
‘WILW1′: {’fx’: ‘8.1′, ‘obtime’: ‘2009-11-07 06:45:00′, ‘ob’: ‘6.9′},
‘GRRW1′: {’fx’: ‘12.8′, ‘obtime’: ‘2009-11-07 04:15:00′, ‘ob’: ‘6.7′}
}

I’ve gone into the keys once and then again,

for k in keys:
for k2 in keys2:
if k2 == ‘ob’:
append to array or something…?
but it seems like I would have to keep track of the inner keys in an array, and then by that point I completely confuse myself. Thanks for your help!

–Jonathan

By: Parand

Parand — Fri, 06 Nov 2009 18:52:26 +0000

Jonathan, what do you mean by sort? Are you looking to access the dictionary in key sort order? The above class is still just a dictionary underneath, so you could do the normal key access functions on it; something like:

keys = car_details.keys()
keys.sort()
for k in keys: print car_details[k]

By: Jonathan

Jonathan — Fri, 06 Nov 2009 13:24:47 +0000

I’m restricted to python 2.4 and was wondering how can I sort by a particular key/value pair using the technique here which makes the dictionaries a class?

Thanks for your help!

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By: Alexander Mikhalev

Alexander Mikhalev — Mon, 08 Sep 2008 10:27:35 +0000

Plus sign was eaten in comments. It should be plus equal one.

By: Alexander Mikhalev

Alexander Mikhalev — Fri, 29 Aug 2008 12:37:46 +0000

To Sam:
car_details['Ford']['Mustang'] = 1 will increment value

By: sam

sam — Wed, 04 Jun 2008 00:06:44 +0000

I’m a newbie as well. My programming language is Perl. But I’m trying to switch into programming in Python. One of the things I miss about Perl which I can’t find in Python is autovivification of hash of hashes (or dictionary of dictionaries in python i suppose). This seems to be the solution. But what I want to find out is how to automatically increment entries like:

car_details['Ford']['Mustang'] = 1
car_details['Toyota']['Corolla'] = 1

So in the above, I want to count the number for each one. In perl all I need to do is:

$car_details->{’Ford’}->{’Mustang’} ;
$car_details->{’Toyota’}->{’Corolla’} ;

Can you give me some idea?

Thanks,
Sam

By: Justin

Justin — Tue, 17 Jul 2007 21:43:42 +0000

I’m a newbie at Python – got the multidimensional dictionary to work (thanks so much for such a clear & concise solution to a common problem). I was trying to figure out how to do an N-D dictionary without the lambda functions (I love them, but I can’t pickle the function…). I can get the one to work, giving me a 2D, but I can’t figure out how to nest them. Could anyone help? Greatly appreciated.

By: KRR

KRR — Tue, 18 May 2004 06:51:57 +0000

It may not be exactly your scenario, but something of this kind will help you even in your scenario based on the input file.

dictionary.python
===============

f = open(’firewall.info’, ‘r’);
dict = {}
dict1 = {}
for line in f.readlines():
d = line.split(’-')
d1 = d[1].split()
for item in d1:
item1 = item.split(’:')
dict[item1[0]] = item1[1]
dict1[d[0]] = dict
print “dict1 “, dict1['firewall1']['ip']
print “dict1 “, dict1['firewall1']['name']
print “dict1 “, dict1['firewall1']['version']
print “dict1 “, dict1['firewall1']
print “dict1 “, dict1

===============

Example file content: firewall.info
==========================

firewall1-name:FW1 version:7x ip:1.1.1.1
firewall2-name:FW2 version:8x ip:2.2.2.2
firewall3-name:FW3 version:9x ip:3.3.3.3
firewall4-name:FW4 version:10x ip:4.4.4.4

output:
=======
#python dictionary.python

dict1 4.4.4.4
dict1 FW4
dict1 10x
dict1 {’ip’: ‘4.4.4.4′, ‘version’: ‘10x’, ‘name’: ‘FW4′}
dict1 {’firewall1′: {’ip’: ‘4.4.4.4′, ‘version’: ‘10x’, ‘name’: ‘FW4′}, ‘firewall3′: {’ip’: ‘4.4.4.4′, ‘version’: ‘10x’, ‘name’: ‘FW4′}, ‘firewall2′: {’ip’: ‘4.4.4.4′, ‘version’: ‘10x’, ‘name’: ‘FW4′}, ‘firewall4′: {’ip’: ‘4.4.4.4′, ‘version’: ‘10x’, ‘name’: ‘FW4′}}

———————- KRR ———-