Why am I getting a NameError with below code?

Question

I am getting a name error with the variable data_A and I cannot figure out why...any help appreciated. Thanks! the variable of concern is data_A

import sys
import csv
import statistics
#modularizing week1 program
def main():

    try:
        column = int(sys.argv[1])
        filename = sys.argv[2]
        with open(filename,'r') as csv_file:
            csv_x = csv.reader(csv_file, delimiter=' ', skipinitialspace=True)
            data_A = [float(line[column-1]) for line in csv_x if (float(line[column-1]))!=-9999.0]
    except:
        column = int(sys.argv[1])
        csv_x = csv.reader(sys.stdin, delimiter= ' ', skipinitialspace=True)
        data_A = [float(line[column-1]) for line in csv_x if (float(line[column-1]))!=-9999.0]

#statistical analysis for data
print(
    'min:', min(data_A),
    'max:', max(data_A),
    ', average:', mean(data_A),
    ', median:', median(data_A)
)

def compute_stats(values):
    import statistics

    if values == []:
        return(None,None,None,None)
    else:
        minimum = min(values)
        maximum = max(values)
        mean = statistics.mean(values)
        median = statistics.median(values)
        return(minimum,maximum,mean,median)

#call main function if code is not working
if __name__ == "__main__":
    main()

score 0 · Answer 1 · answered Apr 12 '21 at 05:53

You are receiving the name error because the scope of "data_A" is within enclosing method i.e. main(). Hence, "data_A" is not visible outside of main().

One way you can avoid this is by moving your print() inside main()

e.g.

def main():
    try:
        data_A = "localized"
    except Exception as e_x:
        data_A = "exception"

print(data_A)

if __name__ == "__main__":
    main()

Traceback (most recent call last):
  File "<string>", line 9, in <module>
NameError: name 'data_A' is not defined

Moving print inside main() resolves, e.g.

def main():
    try:
        data_A = "localized"
    except Exception as e_x:
        data_A = "exception"

    print(data_A)

if __name__ == "__main__":
    main()


> localized

Why am I getting a NameError with below code?

1 Answers1