Python - Multidimensional arrays?

[QUantumAnenome]

I just figured out how to do arrays in python.
I have a C++ program that spits out a binary float array
float f[8][5][60];

In python script that reads it in, I do this right now:

f = file("d:/float.bin", "rb")
a = array('f')
a.fromfile(f, 8*5*60)

And I do the indexing math myself to get an element.

What is the preferred method for using multidimensional arrays in python?

THanks.

[teknomage1]

I think you can just naturally nest lists

Python 2.4 (#1, Mar 22 2005, 21:42:42)
>>> a = [1,[2,3],4]
>>> a
[1, [2, 3], 4]
>>> a[2]
4
>>> a[1][1]
3
>>> a.append(5)
>>> a[3]
5
>>> a
[1, [2, 3], 4, 5]

[QUantumAnenome]

Thanks, but I don't see how that is better. The code to read in the file and insert floats into 3 deep nested lists would be much more complex, and would it also be slower than using a 1D array and indexing into it myself to fake a 3D array? The benefit looks like a syntaticl one, in that I can write a[x][y][z] instead of a(x, y, z).

[teknomage1]

Sorry, maybe redhead will respond since he actually uses python.

[redhead]

Originally Posted by teknomage1

maybe redhead will respond since he actually uses python

Sorry tekno, I dont use python at a regular basis, I know of it and how it should be used, but I'm not currently involved in projects developed in the language. Thats why I havn't listed it as one of my known programming languages.

QUantumAnenome, In a case like the one you're looking for, you'd use the Comma Separated Values module. Simply have your file comma seperated, or tab or whatever you like, and use the module to convert it back to your orriginal list.

Say you're using Excel as the delimiter you can store and retrieve your data in a matter like this:

import csv

a=[1,2,3,[4,5],6,[7,8,[9]],0]

writer = csv.writer(open("my_file", "wb"), csv.excel)
writer.writerows(a)
writer.close()

b=array()
reader = csv.reader(open("my_file", "rb"), csv.excel)
try:
    for row in reader:
        b.append(row)
except csv.Error, e:
    sys.exit('file %s, line %d: %s' % (filename, reader.line_num, e))
reader.close()

print a
print b

Or perhaps you just want the easy and quick answer to this one... By using the pickle serialization

import pickle
a = [1,2,3,[4,5,6],7,[8,[9]],0]
output = open('my_file', 'wb')
pickle.dump(a, output)
output.close()

input = open('my_file', 'rb')
b = pickle.load(input)
input.close()

print a
print b

a == b

[teknomage1]

Originally Posted by redhead

Sorry tekno, I dont use python at a regular basis, I know of it and how it should be used, but I'm not currently involved in projects developed in the language. Thats why I haven't listed it as one of my known programming languages.

D'oh! Sorry to put you on the spot like that, I just searched the forum for the last couple answers to python questions.

[redhead]

Dont feel bad, I like a challenge once in a while.. And it's not like Python has the most complex syntax tree to get involved with.

I would much rather be forced to explain something in python than in forinstance the ZT language or BrainFsck language or perhaps the Whitespace language

Now that would be a challenge in itself...