CODEWITHSUNDEEP
pythonlistdictionaryreadfile
Ben
Ben

Reputation: 33

Turning a two dimensional list into a dictionary in python

Ok, so I have read in a text file from a .txt file that came in the format as such:

home school 5
home office 10
home store 7
school store 8
office school 4
END OF FILE

I then turned it into a two dimensional list in python and it looks something like:

[['home', 'school', '5'], ['home','office','10'],['home','store','7'],
['school','store','8'], ['office','school','4']]

But the way that I would really like it is to be more in dictionary format such as:

{'home': {'school': 5, 'office': 10, 'store': 7},
'school': {'store': 8},
'office': {'school': 4}}

That format looks a lot better and is easier to read. The data that I have is lot more in detail but this is simple version. I have read my text file as follows:

myFileOpen = open(myInputFile, 'r')
myMap = myFileOpen.readlines()[:-1]

#Format the list, each line becomes a list in a greater list
myMap = [i.split('\n')[0] for i in myMap]
myMap = [i.split(' ') for i in myMap]

If anyone can help explain how to this I'd be very grateful! Thank you!

Upvotes: 2

Views: 7352

Answers (4)

Tadeck
Tadeck

Reputation: 137320

The code may look like this:

result = {}
for item in data:
    result.setdefault(item[0], {}).update({item[1]: item[2]})

Proof with whole code: http://ideone.com/8XUA41

Upvotes: 2

dilbert
dilbert

Reputation: 3098

And the hack answer goes to:

txt =\
'''
home school 5
home office 10
home store 7
school store 8
office school 4
'''

txt = txt.strip()
gs = [line.split(" ") for line in txt.split("\n")]
ts = {}
[ts.setdefault(x, {}).setdefault(y, z) for (x, y, z) in gs]
print ts

Upvotes: 1

TerryA
TerryA

Reputation: 59974

It's messy, but it works with a defaultdict:

>>> from collections import defaultdict
>>> L = [['home', 'school', '5'], ['home', 'office', '10'], ['home', 'store', '7'], ['school', 'store', '8'], ['office', 'school', '4']]
>>> d = defaultdict(list)
>>> for i in L:
...     d[i[0]].append(i[1:])
...
>>> {k: dict(v) for k, v in d.items()} # Or d.iteritems with python 2.x
{'home': {'school': '5', 'store': '7', 'office': '10'}, 'school': {'store': '8'}, 'office': {'school': '4'}}

I'm not that experienced with using defaultdicts, so there's probably a better way.

Upvotes: 0

Blender
Blender

Reputation: 298156

Skip the intermediate list and just do it all at once:

d = {}

with open(myInputFile, 'r') as handle:
    for line in handle:
        if line == 'END OF FILE':
            continue

        key1, key2, value = line.split()

        if key1 not in d:
            d[key1] = {}

        d[key1][key2] = int(value)

You could further condense that last part into:

d.setdefault(key1, {})[key2] = int(value)

Upvotes: 1

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