import csv file: integers appearing as floating points

asked 2013-05-20 10:17:16 +0100

GingerAndy
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updated 2013-05-20 16:11:27 +0100

vdelecroix
7645 ●20 ●85 ●168 http://www.labri.fr/pe...

Hi,

I am trying to import a csv file in order to create an adjacency matrix and then plot the associated directed graph. I upload the csv file and use its content to generate a matrix as follows

sage: import csv                           
sage: data = list(csv.reader(file(DATA+'matrix23.csv')))
sage: m = matrix([[ float(_) for _ in line] for line in data])
sage: m

Whereas my csv file only contains integers 1's and 0's, the generated matrix is floating point 1.0's and 0.0's!

Note: the CSV file was created using MS Excel with cells formated to zero decimal places. I'm new to both python and sage and can't find anything on the forums to help

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answered 2013-05-20 11:25:42 +0100

tmonteil
27423 ●31 ●204 ●517 http://wiki.sagemath.o...

updated 2013-05-20 11:33:45 +0100

If your matrix m only contains entries like 0.O and 1.0, you can try to transform it back to an integer matrix:

sage: n = m.change_ring(ZZ)

You can also transform your entries into integers while creating your matrix:

sage: m = matrix([[ ZZ(_) for _ in line] for line in data])

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answered 2013-05-20 12:57:43 +0100

GingerAndy
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Thanks that works a treat.

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