获取python csv文件的第二列作为整数数组

Question

I have a csv file that is as follows:

                #just want this row as array of ints
8/8/2016 0:00   15804300.00     
8/9/2016 0:00   15805850.00     
8/10/2016 0:00  15807737.50
...

I want to get just the second column of numbers (15804300.00...) as an array of integers so it's like:

[15804300.00, 15805850.00, 15807737.50...]

I'm getting type casting errors but this is what I have so far:

filename = 'data.csv' 
with open(filename, 'rb') as f:
    reader = csv.reader(f)
    dataList = list(reader)

    num = []
    for row in dataList:
        num.append(row[0].strip().split('\t'))   #split by tab 

Any suggestions? Is there an easier way to do this? Thank you!

Answer 1

If your data is tab delimited , tell the csv.reader() object to use that delimiter. There should not be any reason to split manually:

filename = 'data.csv' 
with open(filename, 'rb') as f:
    reader = csv.reader(f, delimiter='\t')
    num = [float(row[1]) for row in reader]

The list comprehension then picks out the second column of each row, converting the string to a float value.

Demo:

>>> import csv
>>> demodata = BytesIO("""\
... 8/8/2016 0:00\t15804300.00
... 8/9/2016 0:00\t15805850.00
... 8/10/2016 0:00\t15807737.50
... """)
>>> with demodata as f:
...     reader = csv.reader(f, delimiter='\t')
...     num = [float(row[1]) for row in reader]
...
>>> num
[15804300.0, 15805850.0, 15807737.5]

Answer 2

This works

import csv
filename = 'data.csv'
with open(filename, 'rb') as f:
    reader = csv.reader(f, delimiter='\t')
    dataList = list(reader)
    num = []
    for row in dataList:
        num.append(float(row[0].strip().split(' ')[-1]))   #split with spaces, and extract the last item, as it is always the last one

    print num #[15804300.0, 15805850.0, 15807737.5]