Merge pull request #93 from PdxCodeGuild/kacey-lab07-ccv

lab07 complete

Author: nathanBonilla

code/kaceyb/python/lab07/lab_07.py

@@ -0,0 +1,76 @@
+# 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!
+
+# 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:
+
+
+def credit_card_validator(credit_card_number):
+
+    # Convert the input string into a list of ints
+
+    input_list = list(credit_card_number)
+
+    for i in range(len(input_list)):
+        input_list[i] = int(input_list[i])
+
+    print(input_list)
+    # Slice off the last digit. That is the check digit.
+
+    check_digit = input_list.pop(-1)
+    # print(check_digit)
+    print(input_list)
+    # Reverse the digits.
+    input_list.reverse()
+    print(input_list)
+
+    # Double every other element in the reversed list (starting with the first number in the list).
+
+    doubled_list = []
+    
+
+    for i in range(len(input_list)):
+        if i % 2 == 0:
+            # input_list[i] = (input_list[i]) * 2
+            doubled_list.append(input_list[i]*2)
+        else:
+            # input_list[i] = input_list[i]
+            doubled_list.append(input_list[i])
+            
+    print(doubled_list)
+
+    # Subtract nine from numbers over nine.
+
+    subtract_nine = doubled_list
+
+    for i in range(len(subtract_nine)):
+
+        if (subtract_nine[i]) > 9:
+            subtract_nine[i] = (subtract_nine[i]) - 9
+
+    print(subtract_nine)
+
+    # Sum all values.
+    sum_values = str(sum(subtract_nine))
+    print(sum_values)
+
+    # Take the second digit of that sum.
+    second_digit = int(sum_values[1])
+    print(second_digit)
+    # If that matches the check digit, the whole card number is valid.
+    answer = second_digit == check_digit
+    # Return a boolean
+
+    return answer
+
+
+print(credit_card_validator("4556737586899855"))