将CSV文件读入一个numpy数组，返回none

Question

I am trying to read a CSV data set into a two-dimensional numpy array and then return said array. I continue to get a return none message and am unsure of my approach to this problem - I am new to numpy.

To be clear, the data set contains has two columns and about 100 rows of data. I want to create an array that consists of the first column of data being the x co-ordinates and the second column of data being the y co-ordinates.

import numpy as np 

data = open("mydata.csv")
read = data.read()

def generatingArray(read):
    for data in read:
        dataPoints = np.array(read[0], read[1])

        return dataPoints

print(generatingArray(dataFile))

When I call the function it returns 'None.' Playing around with the placement of the return statement typically gives me an error message. Any suggestions on how to adjust my code would be greatly appreciated.

Answer 1

First thing is change the variable name 'read' to something else. It is a bad practice to use variable names sharing with built-in methods/keywords.

X=[]
Y=[]
with open('mydata.csv','r') as f:
#opens file for reading
    for line in f:#this reads a line
         a,b=line.split()
         X.append(a)
         Y.append(b)
      #appends first element to listX second to Y

Use with-open when you have to read a line. Since a line has two space seperated values ,you split it and extract the two values and append it to lists X and Y containing X and Y coordinates. Now if you want to have a numpy array use this: ar=np.array([X,Y]) [X,Y] is a 2Dlist and no.array converts a list to numpy array.