Reading data from a CSV file yields TypeError-CodePudding

I have a csv file with the following data stored as uncov_users.csv: 2867,2978

I am trying to get the data from the CSV file and print it but I am getting an error. I need the data in separate variables so I am using the for i,j loop.

My Code:

import numpy as np
uncov_users = np.genfromtxt('ucov_users.csv', delimiter=',')
for i,j in uncov_users:
    ux_coor = i  
    uy_coor = j  
    print(ux_coor,uy_coor)

Error:

Traceback (most recent call last):
  File "D:\Programmes\Final_Year\Plot_DFO\test.py", line 3, in <module>
    for i, j in uncov_users:
TypeError: cannot unpack non-iterable numpy.float64 object

I am just trying to understand what is wrong with it and how can it be fixed.

CodePudding user response：

Try this:

import numpy as np

text = open("ucov_users.csv", "r")
text = ''.join([i for i in text]) \
    .replace(" ", "\n")
x = open("ucov_users.csv", "w")
x.writelines(text)
x.close()


uncov_users = np.genfromtxt('ucov_users.csv', delimiter=',')
for i,j in uncov_users:
    ux_coor = i  
    uy_coor = j  
    print(ux_coor,uy_coor)

CodePudding user response：

Use pandas. You can put you csv in a dataframe, then convert you columns into numpy arrays :

import pandas
import numpy as np

dataframe = pandas.read_csv('ucov_users.csv', delimiter=',')
ux_coord = np.array(dataframe.iloc[:, 0])
uy_coord = np.array(dataframe.iloc[:, 1])

CodePudding user response：

Your uncov_users variable is the wrong shape. For the loop

for i,j in uncov_users:
   # stuff ...

to work, uncov_users would need to be a 2d array with two columns, so that i could be assigned a value from the first column and j a value from the second columm.

This problem would be easier to see if you rewrote your for loop like this:

for row in uncov_users:
   i,j = row
   # stuff ...

For the uncov_users array that you have, row is just a number (or to be precise, a numpy.float64 object), so it can't be unpacked. It doesn't have two components that could be assigned to the variables i and j.

Probably the simplest way to fix this would be to use the numpy.atleast_2d() function, e.g,

uncov_users = np.atleast_2d(np.genfromtxt('ucov_users.csv', delimiter=','))

This way, if the file ucov_users.csv has only one row with two columns, the array uncov_users will still have two columns, instead of being a 1d array with two elements. (Of course, this assumes that ucov_users.csv always has two columns.)

CodePudding user response：

Use:

  for row in uncov_users:
    ux_coor, uy_coor = row
    print(ux_coor,uy_coor)