Using python 3.6 How do I incorporate 0 or negative input to raise an error and let the user try again? like len(header): print(Invalid choice!!

Using python 3.6

How do I incorporate 0 or negative input to raise an error and let the user try again?

like <=0

#loop to check valid input option.

while True: try: choice = int(input('Enter choice: ')) if choice>len(header): print("Invalid choice!! Please try again and select value either:",end=" ") for i in range(1,len(header)+1): print(i,end=",") else: break choice = int(input(' Enter choice: ')) except ValueError as ve:print('Invalid response, You need to select the number choice from the option menu') # Catch your local ValueError and continue your loop usr_choice = header[choice - 1]

max_val = None max_obj = None

--here is the full code --

import os.path

import sys, traceback

def main():

print('Welcome to CSV Analytics!')

try:

fname = None

# running an infinite loop and will break only will another attribute and another file choice selected as 'n'

while True:

# will take file name input only when fname is not None

if fname is None:

fname = input('Enter the name of the file you would like to process: ')

if not validateFile(fname):

fname = None

continue

# obtaing header from the file

with open(fname) as fp:

header = fp.readline().strip().split(',')

# first column is object name, so skipping that and getting rest of the columns

header = header[1:]

seq = 1

# printing the options menu which are header in the file

for attribs in header:

print(str(seq)+'.', attribs)

seq += 1

#loop to check valid input option.

while True:

try:

choice = int(input('Enter choice: '))

if choice>len(header):

print("Invalid choice!! Please try again and select value either:",end=" ")

for i in range(1,len(header)+1):

print(i,end=",")

else:

break

choice = int(input(' Enter choice: '))

except ValueError as ve:print('Invalid response, You need to select the number choice from the option menu') # Catch your local ValueError and continue your loop

usr_choice = header[choice - 1]

max_val = None

max_obj = None

# finding maximum value for the given attribute selection

for line in fp:

attr_list = line.strip().split(',')

# when max_val is none set the max_val and max_obj to attribute of first line

if max_val is None:

max_val = attr_list[choice]

max_obj = attr_list[0]

# verifying maximum value of given attribute choice here

if attr_list[choice] > max_val:

max_val = attr_list[choice]

max_obj = attr_list[0]

print('Largest', usr_choice, 'value is', max_obj, 'with', max_val)

another_attr = input('Would you like to conduct another analysis on an attribute? (y/n) ')

if another_attr == 'y':

continue

else:

while True:

another_file = input('Would you like to evaluate another file? (y/n) ')

if another_file == 'y':

fname = input('Enter the name of the file you would like to process: ')

if validateFile(fname):

break

else:

continue

else:

return

# catches all file I/O errors

except IOError:

print('Errored while doing I/O operations on the file')

#traceback.print_exc(file=sys.stdout)

# all non file I/O errors captured here

except:

print('An error occurred')

#traceback.print_exc(file=sys.stdout)

def validateFile(fname):

if os.path.exists(fname):

return True

else:

print('File not found, try with correct file name')

return False

if __name__=='__main__':

main()