credit card

Author: chad5lattimer

Code/chadL/Python/lab6.py

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+#Lab 6: Credit Card Validation
+"""
+Let's write a function credit_card_validator which returns whether a string containing a credit card number is valid as a boolean. 
+The steps are as follows:
+
+Convert the input string into a list of ints
+Slice off the last digit. That is the check digit.
+Reverse the digits.
+Double every other element in the reversed list (starting with the first number in the list).
+Subtract nine from numbers over nine.
+Sum all values.
+Take the second digit of that sum.
+If that matches the check digit, the whole card number is valid.
+Here is a valid credit card number to test with: 4556737586899855
+
+For example, the worked out steps would be:
+
+4 5 5 6 7 3 7 5 8 6 8 9 9 8 5 5
+4 5 5 6 7 3 7 5 8 6 8 9 9 8 5
+5 8 9 9 8 6 8 5 7 3 7 6 5 5 4
+10 8 18 9 16 6 16 5 14 3 14 6 10 5 8
+1 8 9 9 7 6 7 5 5 3 5 6 1 5 8
+85
+5
+True Valid!
+"""
+
+
+
+user_input = input("please enter your credit card numbers ")
+user_input = list(user_input)
+
+def card_number(user_input):
+    number_list = []
+    reversed_card = []
+    card9 = []
+    for l in user_input:
+       number_list.append(int(l))
+    verify_digit1 = number_list.pop()                      #taking off last digit
+    
+    for l in number_list[::-1]:                         #loop through reversed order
+        reversed_card.append(l)
+    counter = 0
+    for l in reversed_card[0::2]:                   #multiply number pulled out
+        num = (l*2)
+        reversed_card[counter] = num
+        counter +=2 
+    for l in reversed_card:                     #take 9 from value if over 9
+        if l > 9:
+                I9 = l - 9 
+                card9.append(I9)
+        else:
+                card9.append(l)
+    card_sum = 0                        #sum of all itms
+    for l in card9:
+        card_sum +=l
+    card_total = str(card_sum)
+    check_digit = card_total[-1]
+    check_digit = int(check_digit)
+    
+    if verify_digit1 == check_digit:
+        return True
+    else: 
+         return False
+card_number(user_input)
+valid = card_number(user_input)
+if valid == True:
+    print("credit card is valid")
+elif valid == False:
+    print("number is not valid")
+           
+
+
+     
+
+"""
+Let's write a function credit_card_validator which returns whether a string containing a credit card number is valid as a boolean. The steps are as follows:
+
+Reverse the digits.
+Double every other element in the reversed list (starting with the first number in the list).
+Subtract nine from numbers over nine.
+Sum all values.
+Take the second digit of that sum.
+If that matches the check digit, the whole card number is valid.
+Here is a valid credit card number to test with: 4556737586899855
+
+For example, the worked out steps would be:
+
+4 5 5 6 7 3 7 5 8 6 8 9 9 8 5 5
+4 5 5 6 7 3 7 5 8 6 8 9 9 8 5
+5 8 9 9 8 6 8 5 7 3 7 6 5 5 4
+10 8 18 9 16 6 16 5 14 3 14 6 10 5 8
+1 8 9 9 7 6 7 5 5 3 5 6 1 5 8
+85
+5
+True Valid!
+
+------option 1-------
+card_no = '4556737586899855'
+c_card = []
+for char in card_no:
+    c_card.append(int(char))
+------option 1-------
+
+------option 2--------------
+c_card = list(card_no)
+for i in range(len(c_card)):
+    card[i] = int(card_no[i])
+ ------option 2--------------
+ 
+ ------- option 3 -----------
+ list_cc = [int(x) for char in card_no]  
+------- option 3 -----------
+
+------option 4 -----------------
+list_cc = list(map(int, card_no))
+list_cc = list(mapped_cc)
+------option 4 -----------------
+
+check_digit = c_card.pop()
+
+c_card = c_card[::-1]      or c_card.reverse()    or    c_card = list(reversed(c_card))
+-----option 1---------
+for index, value in enumerate(c_card):
+    if num % 2 == 0:
+        c_card[num] = value * 2
+
+
+
+for index, value in enumerate(c_card):
+    if value >9:
+        c_card[index] = value - 9
+        
+or
+c_card = [n-9 if n> 9 else n for n in c_card]
+
+
+total = sum(c_card)
+
+#take 2nd digit of that sum
+last_digit = total % 10
+
+
+if las_digit ==check_digit:
+
+else:
+    print("invalid credit card)
+
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+
+"""
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