Not able to sum values while using numpy

Question

I have created a script for calculating the sum of all the values in 32th column which has comma as delimiter. My script is printing the values but unable to sum the values. What I am doing wrong? Below is my script:

import numpy as np
b=np.loadtxt(r'FileP3806520150316142845.txt',dtype=str,delimiter=',',skiprows=0,usecols=(31,))
print b
a = b[1].sum(0)
print a

I can print variable b, but not a.

python myreport.sh 
['1' '438' '18' '987' '1472' '95' '52' '2' '22' '137' '7' '22']
Traceback (most recent call last):
File "myreport.sh", line 4, in <module>
a = b[1].sum(0)
TypeError: cannot perform reduce with flexible type

Also I am just running this script on one file. Can this be applied to all files in a folder or all files in a tar file?

The elements of b are strings, not a numeric type.

jedwards
– jedwards

2015-03-16 09:49:03 +00:00
Commented Mar 16, 2015 at 9:49 — jedwards
– jedwards, Commented Mar 16, 2015 at 9:49

André Laszlo · Accepted Answer · 2015-03-16 09:52:28Z

3

Try setting dtype=int. Numpy doesn't know what to do with a bunch of strings.

You can also convert b after the fact:

b_ints = np.int_(b)

answered Mar 16, 2015 at 9:52

André Laszlo

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3 Comments

user2922822 Over a year ago

Yes thanks. setting dtype to int worked. Is there a way that I can apply this script to all files in a folder, or all files in a zip?

André Laszlo Over a year ago

Many different ways! ☺ Try searching for that here on SO.

André Laszlo Over a year ago

stackoverflow.com/questions/3964681/… for example

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