As a computer science student we were given an assignment to do binary search in python. I don't know what's wrong with my code everything seems just fine
when the searched item is in the middle everything works just fine but whenever I enter a different index position it gets stuck in the while loop.
def binary_search():
ordered_list = [0,1,2,3,4,5,6,7,8,9]
lower_bound = 0
upper_bound = 10
index = int((lower_bound + upper_bound) / 2)
item_f = int(input("please enter the number you want to find (1-10): "))
t = True
while t:
if ordered_list[index] == item_f:
print(f"number {item_f} is found at index position {index}")
t = False
elif item_f > ordered_list[index]:
lower_bound = index + 1
elif item_f < ordered_list[index]:
lower_bound = index - 1
if t == False:
print("number found")
else:
pass
binary_search()
I have added 1 line of code, please check it should working
def binary_search()
ordered_list = [0,1,2,3,4,5,6,7,8,9]
lower_bound = 0
upper_bound = 10
index = int((lower_bound + upper_bound) / 2)
item_f = int(input("please enter the number you want to find (1-10): "))
t = True
while t:
if ordered_list[index] == item_f:
print(f"number {item_f} is found at index position {index}")
t = False
elif item_f > ordered_list[index]:
lower_bound = index + 1
elif item_f < ordered_list[index]:
upper_bound = index - 1#Edit line
index = int((lower_bound + upper_bound) / 2) #Added line
if t == False:
print("number found")
else:
pass
binary_search()
def myNames():
names = []
while True:
a = input("Enter Name: ")
if a != "done":
names.append(a)
elif a == "done":
return names
def all_lengths(myNames):
num_of_strings = len(myNames)
total_size = 0
for item in myNames:
total_size += len(item)
ave_size = float(total_size) / float(num_of_strings)
print(ave_size)
all_lengths(myNames())
def longestWord(myNames):
count = 0
for i in myNames:
if len(i) > count:
count = len(i)
word = I
print ("the longest string is ", word)
how can I make it print the longest name that was inputted by the user for example: out of Samantha and John it would say that Samantha was the longest name
longestName = ""
for name in myNames:
if len(name) > len(longestName):
longestName = name
print("The longest name is", longestName)
This will check the length of each username, and if the name of that username is longer than the current longest username, it will replace it.
You already have the function for it.
Just need to call the function longestWord().
Write longestWord(myNames()) at the end of the program. Right after,
def longestWord(myNames):
count = 0
for i in myNames:
if len(i) > count:
count = len(i)
word = i # Need to type I in lower case
print ("the longest string is ", word)
Update: Since, you don't want the function to ask for names again, you can move the function calling longestWord()inside the above function where it calculates average, with the parameter as myNames i.e.
def myNames():
names = []
while True:
a = input("Enter Name: ")
if a != "done":
names.append(a)
elif a == "done":
return names
def longestWord(myNames):
count = 0
for i in myNames:
if len(i) > count:
count = len(i)
word = i
print ("the longest string is ", word)
def all_lengths(myNames):
num_of_strings = len(myNames)
total_size = 0
for item in myNames:
total_size += len(item)
ave_size = float(total_size) / float(num_of_strings)
print(ave_size)
longestWord(myNames) # Calling the function with already given names
all_lengths(myNames())
So I've been trying to get this code to run:
def conference_call_discount(distance, basic_charge):
if(distance >= 50):
con_calc = basic_charge * 0.5
return con_calc
elif(distance < 50):
con_calc = 0
return con_calc
con_call = str(input("Is it a conference call? "))
from call_charge_functions import conference_call_discount
conference = conference_call_discount(dist, starting_cost)
if con_call == y:
print("your conference call discount is", conference)
else:
conference = 0
However I keep getting this error:
NameError: name 'y' is not defined
I don't know what's wrong
in this if:
if con_call == y:
You didn't set the value for y.
You should set a value for the y variable before comparing it.
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()
Hi having trouble trying to fix an error that occurs when I put just a '#' or rogue value in case someone doesn't want to add any data. I don't know how to fix it and I'm hoping to just end the code just like I would with data.
#Gets Data Input
def getData():
fullList = []
inputText = checkInput("Enter the students first name, last name, first mark, and second mark (# to exit): ")
while inputText != "#":
nameList = []
nameList2 = []
nameList = inputText.split()
nameList2.extend((nameList[0],nameList[1]))
nameList2.append((float(nameList[2]) + float(nameList [3]))/2)
fullList.append(nameList2)
inputText = checkInput("Enter the students first name, last name, first mark, and second mark (# to exit): ")
print("\n")
return fullList
#Calculates Group Average
def calc1(fullList):
total = 0
for x in fullList:
total = total + x[2]
groupAverage = total/(len(fullList))
return(groupAverage)
#Finds Highest Average
def calc2(fullList):
HighestAverage = 0
nameHighAverage = ""
for x in fullList:
if x[2] > HighestAverage:
HighestAverage = x[2]
nameHighAverage = x[0] + " " + x[1]
return (HighestAverage, nameHighAverage)
#Returns Marks above average
def results1(groupAverage,r1FullList):
r1FullList.sort()
print("List of students with their final mark above the group average")
print("--------------------------------------------------------------")
print("{:<20} {:<12}".format("Name","Mark"))
for x in r1FullList:
if x[2] > groupAverage:
name = x[0] + " " + x[1]
print("{:<20} {:<12.2f}".format(name,x[2]))
def calc3(x):
if x[2] >= 80:
return 'A'
elif x[2] >= 65:
return 'B'
elif x[2] >= 50:
return 'C'
elif x[2] < 50:
return 'D'
else:
return 'ERROR'
def results2(fullList):
print("List of Studens with their Final Marks and Grades")
print("-------------------------------------------------")
print("{:<20} {:<12} {:<12}".format("Name","Mark","Grade"))
for x in fullList:
grade = calc3(x)
name = x[0] + " " + x[1]
print("{:<20} {:<12.2f} {:<12}".format(name,x[2],grade))
#Checks for boundary and invalid data
def checkInput(question):
while True:
textInput = input(question)
if textInput == "#":
return textInput
splitList = textInput.split()
if len(splitList) !=4:
print("Invalid Format, Please Try Again")
continue
try:
a = float(splitList[2])
a = float(splitList[3])
if float(splitList[2]) < 0 or float(splitList[2]) > 100:
print("Invalid Format, Please Try Again")
continue
if float(splitList[3]) < 0 or float(splitList[3]) > 100:
print("Invalid Format, Please Try Again")
continue
return(textInput)
except ValueError:
print("Invalid Input, Please Try Again")
continue
#Main Program
#Input Data
fullList = getData()
#Process Data
groupAverage = calc1(fullList)
HighestAverage, nameHighAverage = calc2(fullList)
#Display Results
print("The group average was %.2f" % groupAverage)
print("The student with the highest mark was: %s %0.2f" %(nameHighAverage,HighestAverage))
results1(groupAverage,fullList)
print("\n")
results2(fullList)
Your program works OK for me, unless you enter a # as the first entry, in which case fullList is [] and has length 0. Hence, DivisionByZero at this line: groupAverage = total/(len(fullList)).
You could modify your code to check for this and exit:
import sys
fullList = getData()
if not fullList:
print('No Data!')
sys.exit()