CODEWITHSUNDEEP
pythonstringlistcsv
gdm
gdm

Reputation: 71

Read a csv to a float skipping the first column

S I have a csv file with a bunch of data in it. when I try a few methods to convert the whole thing to a float it gives me an error saying I can not change the contents of the items in the first column to a string (it really just breaks after it hits the first column so my assumption is the contents of the first row are not able to be converted and that is fine).

I would like to be able to skip the first column and convert the rest of my contents to a float.

When I read in my csv file:

with open ('timecards.csv') as tcards:
    tcards = csv.reader(tcards)
    tfloat =[]
    for i in tcards:
        print(i)

I get the output of:

['51-4678119', '7.6', '3.1', '1.4', '4.1', '6.4', '7.7', '6.6']
['87-6664864', '5.2', '3.8', '7.5', '7.8', '7.0', '2.1', '3.6', '7.1', '5.1']
['07-3318962', '2.5', '6.9', '7.9', '7.7', '1.1', '2.6', '5.9', '6.1', '7.5', '3.6']
['06-4413296', '5.9', '4.2', '6.2', '3.1', '2.2', '7.6', '4.7', '6.7', '1.9', '7.4']
['58-5924013', '6.1', '6.2', '1.4', '3.2', '1.4', '1.2', '2.4', '4.4', '5.8', '2.2']
['45-9277595', '6.8', '1.6', '5.1', '3.2', '2.6', '7.1', '4.9', '1.6', '7.2', '2.8']
['04-0002399', '1.1', '6.2', '2.4', '3.8', '2.7', '7.0', '6.2', '2.3', '6.2', '4.3']
['27-7347997', '3.1', '2.1', '4.2', '3.7', '6.5', '7.0', '7.0', '3.9', '3.5', '4.6']
['38-0238479', '7.1', '2.1', '2.7', '6.8', '3.9', '2.6', '2.0', '1.5', '2.6', '1.3']

and so on. I would like to allow my first column to stay a string I guess and convert the rest of my contents to a float. Thanks!

Upvotes: 0

Views: 278

Answers (3)

Willian Vieira
Willian Vieira

Reputation: 736

import csv
with open ('/tmp/timecards.csv') as tcards:
    for i in csv.reader(tcards):
        print([i[0]] + list(map(float, i[1:])))

result:

['51-4678119', 7.6, 3.1, 1.4, 4.1, 6.4, 7.7, 6.6]
['87-6664864', 5.2, 3.8, 7.5, 7.8, 7.0, 2.1, 3.6, 7.1, 5.1]
['07-3318962', 2.5, 6.9, 7.9, 7.7, 1.1, 2.6, 5.9, 6.1, 7.5, 3.6]
['06-4413296', 5.9, 4.2, 6.2, 3.1, 2.2, 7.6, 4.7, 6.7, 1.9, 7.4]
['58-5924013', 6.1, 6.2, 1.4, 3.2, 1.4, 1.2, 2.4, 4.4, 5.8, 2.2]
['45-9277595', 6.8, 1.6, 5.1, 3.2, 2.6, 7.1, 4.9, 1.6, 7.2, 2.8]
['04-0002399', 1.1, 6.2, 2.4, 3.8, 2.7, 7.0, 6.2, 2.3, 6.2, 4.3]
['27-7347997', 3.1, 2.1, 4.2, 3.7, 6.5, 7.0, 7.0, 3.9, 3.5, 4.6]
['38-0238479', 7.1, 2.1, 2.7, 6.8, 3.9, 2.6, 2.0, 1.5, 2.6, 1.3]

Upvotes: 1

Rakesh
Rakesh

Reputation: 82765

This is one approach using map

Ex:

result =[]
with open ('timecards.csv') as tcards:
    tcards = csv.reader(tcards)
    for row in tcards:
        c1, *lst = row    # Column1 and rest of columns 
        result.append([c1] + list(map(float, lst)))

Upvotes: 2

Woodford
Woodford

Reputation: 4449

>>> tcards = [['51-4678119', '7.6', '3.1', '1.4', '4.1', '6.4', '7.7', '6.6'],
              ['87-6664864', '5.2', '3.8', '7.5', '7.8', '7.0', '2.1', '3.6', '7.1', '5.1']]
>>> [[row[0]] + list(map(float, row[1:])) for row in tcards]
[['51-4678119', 7.6, 3.1, 1.4, 4.1, 6.4, 7.7, 6.6],
 ['87-6664864', 5.2, 3.8, 7.5, 7.8, 7.0, 2.1, 3.6, 7.1, 5.1]]
>>> # alternative (maybe simpler?)
>>> [[row[0]] + [float(val) for val in row[1:]] for row in tcards]
[['51-4678119', 7.6, 3.1, 1.4, 4.1, 6.4, 7.7, 6.6],
 ['87-6664864', 5.2, 3.8, 7.5, 7.8, 7.0, 2.1, 3.6, 7.1, 5.1]]

Upvotes: 0

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