Problems with converting a dataset to a Numpy array

Question

I'm traing to convert lines of data into a Numpy array.

This is the first line:

['2013-08-14 00:00:00', '232598', '1.3999999761581', '', '1.1572500056095', '12.302269935608', '51.526794433594', '2.2079374790192', '0.60759371519089', '23.152534484863', '']

Then

import numpy as np
float_data = np.zeros((len(lines), len(header) - 1))
for i, line in enumerate(lines):
 values = [ float(x) for x in line.split(',')[1:]]
 float_data[i, :] = values

I'm getting: ValueError: could not convert string to float: I guess a string whit the value ' ' is the cause of the problem. How can I replace the ' ' with the value 0?

kenxben · Accepted Answer · 2020-06-07 20:21:12Z

1

You could use:

values = [float(x) if len(x) else 0.0 for x in line.split(',')[1:]]

If you are reading a example.txt file like this:

v0,v1,v2,v3,v4,v5,v6,v7,v8,v9,v10
2013-08-1400:00:00,232598,1.3999999761581,,1.1572500056095,12.302269935608,51.526794433594,2.2079374790192,0.60759371519089,23.152534484863,
2013-08-1400:00:00,232598,1.3999999761581,,1.1572500056095,12.302269935608,51.526794433594,2.2079374790192,0.60759371519089,23.152534484863,

This code reads the data into float values and stores them in the float_data array.

file = open("example.txt", "r")
lines = [line.rstrip('\n') for line in file]
header = lines[0].split(',')
lines = lines[1:]
float_data = np.zeros((len(lines), len(header) - 1))

for i, line in enumerate(lines):
    values = [float(x) if len(x) else 0.0 for x in line.split(',')[1:]]
    float_data[i, :] = values

edited Jun 7, 2020 at 20:21

answered Jun 7, 2020 at 3:14

kenxben

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2 Comments

TOTΣM Over a year ago

Whitthis i'm getting: "ValueError: cannot copy sequence with size 0 to array axis with dimension 10"

kenxben Over a year ago

I couldn't reproduce your last error. Are you sure all of the lines are of the same length?

TOTΣM · Accepted Answer · 2020-06-07 22:44:03Z

0

Finally, this worked out for me

import numpy as np
float_data = np.zeros((len(lines), len(header) - 1))
for i, line in enumerate(lines):   
  laLinea = line.split(',')
  for n, k in enumerate(laLinea):
    if k == '':
      laLinea[n] = '0.0'
  laLinea = laLinea[1:]      
  for x in laLinea:    
    values = [float(x)  for x in laLinea] 
    float_data[i, :] = values

answered Jun 7, 2020 at 22:44

TOTΣM

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