Hello this is my first question and sorry I don't know how to phrase it,
I am trying to create a two list. The first list is for one set of codes (code1) and is validated in the VC function. The second function (VC) is to validate the second list. Both functions work well in validating the numbers. However in the third function (add_validations). In that function I want to repeat VC and VQ until the user either types in END or either of the functions return False. When true I want the inputs to be appended into the two separate lists. However, the third function not only does not append any of the list it does not identify/run either of the two functions and comes up with:
TypeError: int() argument must be a string, a bytes-like object or a number, not 'NoneType'
And I'm sorry I didn't know which code to add so I added everything (delete if not allowed sorry):
Code:
def add_validations():
code1 = []
code2 = []
VC()
VQ()
while True:
record = []
i = VC()
q = VQ()
if i != "END":
VQ()
VC()
code1.append(int(i))
code2.append(int(q))
elif VC == True and VQ() == True:
VQ()
VC()
code1.append(int(i))
code2.append(int(q))
elif VC == False and VQ() == True:
print("Invalid code")
else:
print("Invalid quantity")
return code1,code2
def VC():
i = input("What is the item code \n")
minimum = 0
maximum = 39
if i == "END":
i = "END"
return showRecord()
elif int(i) > minimum and int(i) <= maximum:
return int(i)
True
else:
False
def VQ():
q = input("What quanity \n")
minimum = 0
maximum = 49
if q == "END":
isValidCode = "END"
return showRecord()
elif int(q) > minimum and int(q) <= maximum:
True
else:
False
def isempty(qu):
if qu==[]:
return True
else:
return False
def push(qu,item):
qu.append(item)
if len(qu)==1:
front=rear=0
else:
rear=len(qu)-1
def pop(qu):
if isempty(qu):
return "underflow"
else:
item=qu.pop()[0]
if len(qu)==0:
front=rear=0
return item
def peek(qu):
if isempty(qu):
return "underflow"
else:
front=0
return qu[front]
def display(qu):
if isempty(qu):
print("Queue Empty")
else:
front=0
rear=len(qu)-1
print(qu[front],"<--- front")
for a in range(1,rear):
print(qu[a])
print(qu[rear],"<--- rear")
def summation():
def sum_arr(arr,size):
if (size == 0):
return 0
else:
return arr[size-1] + sum_arr(arr,size-1)
n=int(input("Enter number of elements in the queue for addition="))
queue=[]
for i in range(0,n):
queue.append(item)
print("The list is:")
print(queue)
print("sum of items :")
b=sum_arr(queue,n)
print(b)
queue=[]
for i in range(0,4):
print("----Queue Operations----")
print("1.Push/Enqueue")
print("2.Pop/Dequeue")
print("3.Peek")
print("4.Display Queue")
print("5.Exit")
print("6.Summation")
ch=int(input("Enter your choice="))
if ch==1:
item=int(input("Enter element="))
push(queue,item)
elif ch==2:
item=pop(queue)
if item=="underflow":
print("Queue Empty")
else :
print("Popped item=",item)
elif ch==3:
item=peek(queue)
if item=="underflow":
print("Queue Empty")
else:
print("Front most=",item)
elif ch==4:
display(queue)
elif ch==5:
break
elif ch==6:
summation()
else:
print("Invalid Choice")
this is the entire code which we are using here....
this actually for the implementation of queues using lists
it is compulsory to use queues method only here
Enter element=4
Enter element=5
Enter element=6
Enter the number of elements in the queue for addition=3
The list is:
[6, 6, 6]
the sum of items :
18
here the error is that the elements given are 4,5,6 but only the last element '6' is used for finding the sum thrice...
i hope i answered all the queries asked in the comments.....
any ideas with a little explanation are highly appreciated....
Zen of Python: Simple is better than complex
No matter what custom function you build, it will never be faster than a builtin.
l = [6,6,6]
total = sum(l)
print('The list is: {}'.format(l)
print('the sum of items : {}'.format(total))
If you must still need a custom function
def arr_sum(arr):
holder = 0
if len(arr) == 0:
return 0
else:
holder = [holder + i for i in arr if type(i) == int]
return holder
I am writing a file overlap function that takes two arguments: longestFile and shorterFile. I want to see if two files have the same numbers and if they do, it will append that number to an empty list.
These are the two lists I am using for the program:
The first file that I am using to compare and The second file that I use
def longestFile(firstFile, secondFile):
if len(firstFile)>len(secondFile):
return firstFile
else:
return secondFile
def shortestFile(firstFile, secondFile):
if len (firstFile) < len(secondFile):
return firstFile
else:
return secondFile
def middleNumber(theLongestFile):
return theLongestFile[len(theLongestFile)//2]
def fileOverlap(lstFirstFile,lstSecondFile):
lstMatchingNums = []
lstLongerFile = longestFile(lstFirstFile,lstSecondFile)
lstShortestFile = shortestFile(lstFirstFile,lstSecondFile)
for eachLines in range(len(lstShortestFile)):
lstLongerFile = longestfile(lstFirstFile,lstSecondFile)
for eachLine in range(len(lstLongerFile)):
if lstShortestFile[eachLines] == middleNumber(lstLongerFile):
lstMatchingNums.append(lstShortestFile[eachLines])
break
elif lstShortestFile[eachLines] < middleNumber(lstLongerFile):
lstLongerFile = lstLongerFile[0:len(lstLongerFile)//2+1]
if len(lstLongerFile) <= 2 and lstLongerFile[0] == lstShortestFile[eachLines]:
lstMatchingNums.append(lstShortestFile[eachLines])
break
elif middleNumber(lstLongerFile) != lstShortestFile[eachLines] and len(lstLongerFile) <=2:
break
elif lstShortestFile[eachLines] > middleNumber(lstLongerFile):
lstLongerFile = lstLongerFile[len(lstLongerFile)//2:]
if len(lstLongerFile) <= 2 and lstLongerFile[0] == lstShortestFile[eachLines]:
lstMatchingNums.append(lstShortestFile[eachLines])
break
elif middleNumber(lstLongerFile) != lstShortestFile[eachLines] and len(lstLongerFile) <= 2:
break
return lstMatchingNums
lstHappyNums = open('happynumbs.txt','r')
lstReadingHappyLines = lstHappyNums.readlines()
lstHappyNums.close()
lstPrimeNumsFile = open('primenumbers.txt','r')
lstReadingPrimeLines = lstPrimeNumsFile.readlines()
lstPrimeNumsFile.close()
print(fileOverlap(lstReadingHappyLines,lstReadingPrimeLines))
If I was to run this program, it would give me an empty list and I am not sure why.
I'm a beginner Python learner and I'm currently working on Luhn Algorithm to check credit card validation. I wrote most of the code, but I'm stuck with 2 errors I get 1st one is num is referenced before assignment. 2nd one I'm getting is object of type '_io.TextIOWrapper' has no len(). Further help/ guidance will be greatly appreciated.
These are the steps for Luhn Algorithm (Mod10 Check)
Double every second digit from right to left. If this “doubling” results in a two-digit number, add the two-digit
number to get a single digit.
Now add all single digit numbers from step 1.
Add all digits in the odd places from right to left in the credit card number.
Sum the results from steps 2 & 3.
If the result from step 4 is divisible by 10, the card number is valid; otherwise, it is invalid.
Here's what my output is supposed to be
Card Number Valid / Invalid
--------------------------------------
3710293 Invalid
5190990281925290 Invalid
3716820019271998 Valid
37168200192719989 Invalid
8102966371298364 Invalid
6823119834248189 Valid
And here is the code.
def checkSecondDigits(num):
length = len(num)
sum = 0
for i in range(length-2,-1,-2):
number = eval(num[i])
number = number * 2
if number > 9:
strNumber = str(number)
number = eval(strNumber[0]) + eval(strNumber[1])
sum += number
return sum
def odd_digits(num):
length = len(num)
sumOdd = 0
for i in range(length-1,-1,-2):
num += eval(num[i])
return sumOdd
def c_length(num):
length = len(num)
if num >= 13 and num <= 16:
if num [0] == "4" or num [0] == "5" or num [0] == "6" or (num [0] == "3" and num [1] == "7"):
return True
else:
return False
def main():
filename = input("What is the name of your input file? ")
infile= open(filename,"r")
cc = (infile.readline().strip())
print(format("Card Number", "20s"), ("Valid / Invalid"))
print("------------------------------------")
while cc!= "EXIT":
even = checkSecondDigits(num)
odd = odd_digits(num)
c_len = c_length(num)
tot = even + odd
if c_len == True and tot % 10 == 0:
print(format(cc, "20s"), format("Valid", "20s"))
else:
print(format(cc, "20s"), format("Invalid", "20s"))
num = (infile.readline().strip())
main()
You just forgot to initialize num
def main():
filename = input("What is the name of your input file? ")
infile= open(filename,"r")
# initialize num here
num = cc = (infile.readline().strip())
print(format("Card Number", "20s"), ("Valid / Invalid"))
print("------------------------------------")
while cc!= "EXIT":
even = checkSecondDigits(num)
odd = odd_digits(num)
c_len = c_length(num)
tot = even + odd
if c_len == True and tot % 10 == 0:
print(format(cc, "20s"), format("Valid", "20s"))
else:
print(format(cc, "20s"), format("Invalid", "20s"))
num = cc = (infile.readline().strip())
First, maybe you should remove the extra characters:
def format_card(card_num):
"""
Formats card numbers to remove any spaces, unnecessary characters, etc
Input: Card number, integer or string
Output: Correctly formatted card number, string
"""
import re
card_num = str(card_num)
# Regex to remove any nondigit characters
return re.sub(r"\D", "", card_num)
After check if credit card is valid using the Luhn algorithm:
def validate_card(formated_card_num):
"""
Input: Card number, integer or string
Output: Valid?, boolean
"""
double = 0
total = 0
digits = str(card_num)
for i in range(len(digits) - 1, -1, -1):
for c in str((double + 1) * int(digits[i])):
total += int(c)
double = (double + 1) % 2
return (total % 10) == 0
This is a very simpler version of code it is based on lunh's algorithm
def validator(n):
validatelist=[]
for i in n:
validatelist.append(int(i))
for i in range(0,len(n),2):
validatelist[i] = validatelist[i]*2
if validatelist[i] >= 10:
validatelist[i] = validatelist[i]//10 + validatelist[i]%10
if sum(validatelist)%10 == 0:
print('This a valid credit card')
else:
print('This is not valid credit card')
def cardnumber():
result=''
while True:
try:
result = input('Please enter the 16 digit credit card number : ')
if not (len(result) == 16) or not type(int(result) == int) :
raise Exception
except Exception:
print('That is not a proper credit card number. \nMake sure you are entering digits not characters and all the 16 digits.')
continue
else:
break
return result
def goagain():
return input('Do you want to check again? (Yes/No) : ').lower()[0] == 'y'
def main():
while True:
result = cardnumber()
validator(result)
if not goagain():
break
if __name__ == '__main__':
main()
Old thread but the answer concerns me... and the real issue wasn't identified.
Actually, the error is that you have used the identifier (num) for the parameter when defining checkSecondDigits as the identifier/name of the argument when calling the function in the mainline. The function should be called in main() by
even = checkSecondDigits(cc) so the value in cc (which is the argument) is passed into num (as the parameter) for use within the function.
The same rookie error is made with odd_digits and cc_length.
This question (and the initially suggested answer) demonstrates a fundamental mis-understanding of passing arguments to parameters...
The suggested 'declaring' of num just hides this error/misunderstanding and also obfuscates the local and global scopes of num (which should only be local) and cc (which is global) so whilst the suggestion works in this case, it works for the wrong reason and is poor style and bad programming.
Further,
num should not appear anywhere in main() as it should be local to (only appear inside of) the functions called...
The last line in this code should be the same as the first, but the last line incorrectly assigns the data to num instead of cc
cc = (infile.readline().strip())
print(format("Card Number", "20s"), ("Valid / Invalid"))
print("------------------------------------")
while cc!= "EXIT":
even = checkSecondDigits(num)
odd = odd_digits(num)
c_len = c_length(num)
tot = even + odd
if c_len == True and tot % 10 == 0:
print(format(cc, "20s"), format("Valid", "20s"))
else:
print(format(cc, "20s"), format("Invalid", "20s"))
num = (infile.readline().strip())
you can use my code for card validation it is 100% dynamic because of the card structure is stored in CSV file, so it is easy to update here is the code on GitHub profile, python file link, code explanation file link and CSV for datafile link
python code:
# -*- coding: utf-8 -*-
"""
Created on Tue Sep 10 20:55:30 2019
#author: Preyash2047#gmail.com
"""
import csv
import numpy as np
#csv file imported and storf in reader
reader = csv.DictReader(open("card_data.csv"))
#input card number
card_number = input("Enter the card No: ")
#global variable declaration
min_digits=0
max_digits=0
card_number_list = list(card_number)
card_number_list_reverse=card_number_list[::-1]
card_number_length=len(card_number_list)
first_digit = int(card_number_list[0])
#global variable for final output
card_provider_list_number = 0
result_found = False
card_number_digits = 0
mit_name=""
#list
start=[]
end=[]
name=[]
c_d=[]
number_length=[]
min_max_digits_list=[]
#append the list from csv
for raw in reader:
start.append(raw['start'])
end.append(raw['end'])
name.append(raw['name'])
c_d.append(raw['c_d'])
number_length.append(raw['number_length'])
#initialize the value of min_digits & max_digits
def min_max_digits():
global min_digits
global max_digits
for i in range(len(start)):
available_length=number_length[i].split(',')
for j in range(len(available_length)):
min_max_digits_list.append(available_length[j])
min_max_digits_array = np.array(min_max_digits_list)
np.unique(min_max_digits_array)
min_digits=int(min(min_max_digits_array))
max_digits=int(max(min_max_digits_array))
#list to int
def list_to_int(noofdigits):
str1 = ""
return int(str1.join(noofdigits))
#card validation
def iin_identifier():
first_six_digit = list_to_int(card_number_list[0:6])
for i in range(len(start)):
if(first_six_digit >= int(start[i]) and first_six_digit <= int(end[i])):
available_length=number_length[i].split(',')
for j in range(len(available_length)):
if(card_number_length == int(available_length[j])):
global card_provider_list_number
card_provider_list_number = i
global card_number_digits
card_number_digits = available_length[j]
global result_found
result_found = True
#Major Industry Identifier (MII) identification
def mit_identifier():
global first_digit
global mit_name
switcher = {
1: "Airlines",
2: "Airlines",
3: "Travel and Entertainment",
4: "Banking and Financial Services",
5: "Banking and Financial Services",
6: "Merchandising and Banking",
7: "Petroleum",
8: "Health care, Telecommunications",
9: "National Assignment"
}
mit_name=switcher.get(first_digit, "MIT Identifier Not Found")
#Luhn Algorithm or modulo-10 Algorithm
def luhn_algorithm():
for i in range(card_number_length):
if(i%2!=0 and i!=0):
card_number_list_reverse[i]=int(card_number_list_reverse[i])*2
#print(str(i)+" "+ str(card_number_list_reverse[i]))
if(len(str(card_number_list_reverse[i]))==2):
even_number_2=list(str(card_number_list_reverse[i]))
card_number_list_reverse[i] = int(even_number_2[0])+int(even_number_2[1])
#print("\tsubsum "+str(i)+" "+str(card_number_list_reverse[i]))
else:
card_number_list_reverse[i]=int(card_number_list_reverse[i])
division_int = int(sum(card_number_list_reverse)/10)
division_float=sum(card_number_list_reverse)/10
if(division_int-division_float==0):
return True
#initial level number length validation
def card_number_validation():
min_max_digits()
if(card_number_length>= min_digits and card_number_length <= max_digits and first_digit != 0):
iin_identifier()
mit_identifier()
if(result_found and luhn_algorithm()):
print("\nEntered Details are Correct\n")
print("\nHere are the some details we know about you card")
print("\nNo: "+card_number)
print("\nIssuing Network: "+name[card_provider_list_number])
print("\nType: "+c_d[card_provider_list_number]+" Card")
print("\nCategory of the entity which issued the Card: "+mit_name)
else:
print("\nCard Number is Invalid\nPlease renter the number!\n")
else:
print("\nCard Number is Invalid\n")
#method called to run program
card_number_validation()
n = input("Enter 16-digit Credit Card Number:")
lst = []
for i in range(16):
lst.append(n[i])
# print(lst)
# list1 = n.split()
# print(list1)
def validate_credit_card():
global lst
if len(lst) == 16:
for i in range(0, len(lst)):
lst[i] = int(lst[i])
# print(lst)
last = lst[15]
first = lst[:15]
# print(first)
# print(last)
first = first[::-1]
# print(first)
for i in range(len(first)):
if i % 2 == 0:
first[i] = first[i] * 2
if first[i] > 9:
first[i] -= 9
sum_all = sum(first)
# print(first)
# print(sum_all)
t1 = sum_all % 10
t2 = t1 + last
if t2 % 10 is 0:
print("Valid Credit Card")
else:
print("Invalid Credit Card!")
else:
print("Credit Card number limit Exceeded!!!!")
exit()
if __name__ == "__main__":
validate_credit_card()
Like using this to validate that an input is only alpha-numeric:
while True:
str = input('')
if str.isalnum():
break
else:
print("Please include only alpha-numeric characters.\n")
This code has worked for all instances that I have tested it in, but is this bad practice?
That's fine. Here is a note, however: you can find out if the while loop exited with a break or without one by using else:
x = 0
while x < 4:
x += 1
else:
print("no break")
# prints no break
If you break, however:
x = 0
while x < 4:
x += 1
if x == 2:
break
else:
print("no break")
# Does not print
you can abstract it further
def verified_input(prompt='',test_condition=lambda x:1,err_message="Please Enter Valid Input"):
while True:
result = input(prompt)
if test_condition(result):
return result
print( err_message )
def verified_alnum(prompt,err_message="Please enter Only alpha numerics"):
return verified_input(prompt,lambda x:x.isalnum(),err_message)
result = verified_alnum("Enter Password:","A password must be only letters and numbers")
this allows you to create any number of test conditions quickly and relatively verbosely