Fellow python developers. I have a task which I can't seem to crack and my tutor is MIA. I need to write a program which only makes use of while loops, if, elif and else statements to:
Constantly ask the user to enter any random positive integer using int(raw_input())
Once the user enters -1 the program needs to end
the program must then calculate the average of the numbers the user has entered (excluding the -1) and print it out.
this what I have so far:
num = -1
counter = 1
anyNumber = int(raw_input("Enter any number: "))
while anyNumber > num:
anyNumber = int(raw_input("Enter another number: "))
counter += anyNumber
answer = counter + anyNumber
print answer
print "Good bye!"
Try the following and ask any question you might have
counter = 0
total = 0
number = int(raw_input("Enter any number: "))
while number != -1:
counter += 1
total += number
number = int(raw_input("Enter another number: "))
if counter == 0:
counter = 1 # Prevent division by zero
print total / counter
You need to add calculating average at the end of your code.
To do that, have a count for how many times the while loop runs, and divide the answer at the end by that value.
Also, your code is adding one to the answer each time because of the line - answer = counter + anyNumber, which will not result in the correct average. And you are missing storing the first input number, because the code continuously takes two inputs. Here is a fixed version:
num = -1
counter = 0
answer = 0
anyNumber = int(raw_input("Enter any number: "))
while anyNumber > num:
counter += 1
answer += anyNumber
anyNumber = int(raw_input("Enter another number: "))
if (counter==0): print answer #in case the first number entered was -1
else:
print answer/counter #print average
print "Good bye!"
There's another issue I think:
anyNumber = int(raw_input("Enter any number: "))
while anyNumber > num:
anyNumber = int(raw_input("Enter another number: "))
The value of the variable anyNumber is updated before the loop and at the beginning of the loop, which means that the first value you're going to enter is never going to be taken in consideration in the average.
A different solution, using a bit more functions, but more secure.
import numpy as np
numbers = []
while True:
# try and except to avoid errors when the input is not an integer.
# Replace int by float if you want to take into account float numbers
try:
user_input = int(input("Enter any number: "))
# Condition to get out of the while loop
if user_input == -1:
break
numbers.append(user_input)
print (np.mean(numbers))
except:
print ("Enter a number.")
You don't need to save total because if the number really big you can have an overflow. Working only with avg should be enough:
STOP_NUMBER = -1
new_number = int(raw_input("Enter any number: "))
count = 1
avg = 0
while new_number != STOP_NUMBER:
avg *= (count-1)/count
avg += new_number/count
new_number = int(raw_input("Enter any number: "))
count += 1
I would suggest following.
counter = input_sum = input_value = 0
while input_value != -1:
counter += 1
input_sum += input_value
input_value = int(raw_input("Enter any number: "))
try:
print(input_sum/counter)
except ZeroDivisionError:
print(0)
You can avoid using two raw_input and use everything inside the while loop.
There is another way of doing..
nums = []
while True:
num = int(raw_input("Enter a positive number or to quit enter -1: "))
if num == -1:
if len(nums) > 0:
print "Avg of {} is {}".format(nums,sum(nums)/len(nums))
break
elif num < -1:
continue
else:
nums.append(num)
Here's my own take on what you're trying to do, although the solution provided by #nj2237 is also perfectly fine.
# Initialization
sum = 0
counter = 0
stop = False
# Process loop
while (not stop):
inputValue = int(raw_input("Enter a number: "))
if (inputValue == -1):
stop = True
else:
sum += inputValue
counter += 1 # counter++ doesn't work in python
# Output calculation and display
if (counter != 0):
mean = sum / counter
print("Mean value is " + str(mean))
print("kthxbye")
Related
I'm trying to do a def function and have it add the digits of any number entered and stop when I type the number "0", for example:
Enter the number: 25
Sum of digits: 7
Enter the number: 38
Sum of digits: 11
Enter the number: 0
loop finished
I have created the code for the sum of digits of the entered number, but when the program finishes adding, the cycle is over, but what I am looking for is to ask again for another number until finally when I enter the number "0" the cycle ends :(
This is my code:
def sum_dig():
s=0
num = int(input("Enter a number: "))
while num != 0 and num>0:
r=num%10
s=s+r
num=num//10
print("The sum of the digits is:",s)
if num>0:
return num
sum_dig()
Use list() to break the input number (as a string) into a list of digits, and sum them using a list comprehension. Use while True to make an infinite loop, and exit it using return. Print the sum of digits using f-strings or formatted string literals:
def sum_dig():
while True:
num = input("Enter a number: ")
if int(num) <= 0:
return
s = sum([int(d) for d in list(num)])
print(f'The sum of the digits is: {s}')
sum_dig()
In order to get continuous input, you can use while True and add your condition of break which is if num == 0 in this case.
def sum_dig():
while True:
s = 0
num = int(input("Enter a number: "))
# Break condition
if num == 0:
print('loop finished')
break
while num > 0:
r=num%10
s=s+r
num=num//10
print("The sum of the digits is:",s)
sum_dig()
A better approach would be to have sum_dig take in the number for which you want to sum the digits as a parameter, and then have a while loop that takes care of getting the user input, converting it to a number, and calling the sum_digit function.
def sum_dig(num): # takes in the number as a parameter (assumed to be non-zero)
s=0
while num > 0: # equivalent to num != 0 and num > 0
r = num % 10
s = s + r
num = num // 10
return s
while True:
num = int(input("Enter a number: "))
if num == 0:
break
print("The sum of the digits is: " + sum_dig(num))
This enables your code to adhere to the Single-Responsibility Principle, wherein each unit of code has a single responsibility. Here, the function is responsible for taking an input number and returning the sum of its digits (as indicated by its name), and the loop is responsible for continuously reading in user input, casting it, checking that it is not the exit value (0), and then calling the processing function on the input and printing its output.
Rustam Garayev's answer surely solves the problem but as an alternative (since I thought that you were also trying to create it in a recursive way), consider this very similar (recursive) version:
def sum_dig():
s=0
num = int(input("Enter a number: "))
if not num: # == 0
return num
while num>0:
r= num %10
s= s+r
num= num//10
print("The sum of the digits is:",s)
sum_dig()
The question is to write a program that asks the user to enter a series of numbers and output, the maximum number in the series, the minimum number in the series, and the average of all the POSITIVE numbers.
The current code I have calculates for the minimum and maximum, but I don't know how to write a code to make it calculate the average.
maximum = None
minimum = None
num = None
while True:
inp = input("PLease enter a number: ")
if inp == "#" :
break
try:
num=float(inp)
except:
print ("Error with this input")
continue
if maximum is None:
maximum = num
minimum = num
if num>maximum:
maximum=num
if num<minimum:
minimum=num
print ("The Maximum is ", maximum)
print ("The Minimum is ", minimum)
You store all inputted numbers in a list and calculate from there:
def avg_pos(d):
if len(d) == 0: # avoid div by 0
return 0
return sum(d)/len(d)
data = []
while True:
try:
n = input("Number: ")
if n == "#":
break
n = int(n)
data.append(n)
except ValueError:
print("Not a number")
print( f"Min: {min(data)} Max: {max(data)} AvgP: {avg_pos([d for d in data if d>0])}" )
Output:
Number: 4
Number: 5
Number: 6
Number: -2
Number: -99
Number: 73
Number: #
Min: -99 Max: 73 AvgP: 22.0
Find the sum each time a positive number is accepted and count each number. At the end you can determine the average
maximum = None
minimum = None
sum_of_positive = 0
count_of_positive = 0
num = None
while True:
inp = input("PLease enter a number: ")
if inp == "#" :
break
try:
num=float(inp)
except:
print ("Error with this input")
continue
if maximum is None:
maximum = num
minimum = num
if num>maximum:
maximum=num
if num<minimum:
minimum=num
if num > 0:
sum_of_positive = sum_of_positive + num
count_of_positive = count_of_positive + 1
if count_of_positive > 0:
average_of_positive = sum_of_positive / count_of_positive
else:
average_of_positive = 0
print ("The Maximum is ", maximum)
print ("The Minimum is ", minimum)
print ("The Average of Positive Numbers is ", average_of_positive)
You need to add a counter variable to know how many rounds you got in the loop.
And also you need a total variable to sum all the num
Then you just need to print total/counter
Use library functions like max, min and sum.
For example max([1,2,3,5,11,8]) gives you 11, min([1,2,3,5,11,8]) gives you 1 and sum([1,2,3,5,11,8]) gives you 30.
So lets say you read the numbers in to a list named numbers, then getting the maximal number is max(numbers), the minimal is min(numbers) and the average is sum(numbers)/len(numbers).
Please notice that if you use python 2 then you need to convert to float before dividing, like this float(sum(numbers))/len(numbers).
I'm trying to write a 'while' loop that takes a users input, if it is a number it remembers it, if it is a blank space it breaks. At the end it should print the average of all entered numbers. This is giving me the error 'could not convert string to float: '. What exactly is wrong here? Thanks!
EDIT: I re-wrote it like this and I get the same error about converting, but it seems to be on the final (count += 1) line?
number = 0.0
count = 0
while True:
user_number = input('Enter a number: ')
if user_number == ' ':
break
print (number / count)
number = number + float(user_number)
count += 1
My guess is that you directly hit enter when you don't want to pass numbers anymore. In that case, comparing with a space is incorrect.
number = 0.0
count = 0
while True:
user_number = input('Enter a number: ')
if user_number == '':
break
number += float(user_number)
count += 1
print (number / count)
Also a statement after a break is unreachable.
If you want a cleaner alternative, I would recommend appending to a list, and then computing the average. This removes the need for a separate counter. Try this:
numbers = []
while True:
user_number = input('Enter a number: ')
if user_number == '':
break
numbers.append(float(user_number))
print (sum(numbers) / len(numbers))
Additionally, you could remove the need for a break by testing in the head of while, but you'll need to take an additional input outside the loop.
You should change the order, right now you try to convert everything into floats, even blank spaces.
while True:
user_number = input('Enter a number: ')
if not user_number.isdigit():
print (number / count)
break
count += 1
number = number + float(user_number)
Additionally, you should do the print of the average value before the break.
I changed your if condition to break if any input except a number is entered, it should be a bit more general than before.
Change order and it should solve the problem, you should first check is enterned input is string or not then go to number part
#!/usr/bin/python
number = 0.0
count = 0
while True:
user_number = raw_input('Enter a number: ')
if user_number == (' '):
print (number / count)
break
number = number + float(user_number)
count += 1
This should work for you.
lst= []
while True:
user_number = input('Enter a number: ')
if user_number == ' ':
break
lst.append(int(user_number))
print(int(user_number))
print("Average : " + str(sum(lst)/len(lst)))
This code works correctly.
I think you are giving Other than space as input to break.
number = 0.0
count = 0
while True:
user_number = input('Enter a number: ')
if user_number == ' ':
break
print (number / count)
number = number + float(user_number)
count += 1
or else use below code:
--> Break will be triggered for non-digit input.
number = 0.0
count = 0
while True:
user_number = input('Enter a number: ')
if not user_number.isdigit():
break
number = number + float(user_number)
count += 1
print("user_number", number)
print("Count", count)
print (number / count)
I saw a similar post, but it included functions, which mine does not.
Objective: Write a program that reads an unspecific number of integers, determines how many positive and negative values have read, and computes the total and average of the input values (not counting 0's) while the program will halt at 0.
ISSUE I AM HAVING: When using the following test values
1,
2,
-1,
3
I get the following:
The number of positives: 1
The number of negatives: 2
The total amount of numbers used: 3
The average is 1.33 which is 4 / 3
It should be:
The number of positives: 1
The number of negatives: 3
The total amount of numbers used: 4
The average is 1.25 which is 5 / 4
My Attempt below:
positive_number = 0
negative_number = 0
average = 0
count = 0
new_number = 0
user_input = eval(input("Enter enter as many integers as you want, 0 will halt: "))
if user_input == 0:
print("You didn't enter any number, code ended")
else:
while user_input != 0:
user_input = eval(input("Enter enter as many intergers as you want, 0 will halt: "))
if user_input == 0:
print("You didn't enter any number, code ended")
elif user_input != 0 and user_input > 0:
new_number += user_input
positive_number += 1
count += 1
else:
user_input != 0 and user_input < 0
new_number += user_input
negative_number += 1
count += 1
average = (new_number / count)
print("\nThe number of positives:", positive_number)
print("The number of negatives:", negative_number)
print("The total amount of numbers used:", count)
print("The average is", format(average,".2f"), "which is", str(new_number), "/", str(count))
What is causing such error? I can only assume that this is a minor fix?
I've fixed the problems in your code and refactored to trap error conditions and removed unnecessary complications:
positive_number = 0
negative_number = 0
average = 0
count = 0
total = 0
user_input = None
while user_input != 0:
try:
user_input = int(input("Enter enter as many intergers as you want, 0 will halt: "))
except ValueError:
user_input=0
if user_input > 0:
total += user_input
positive_number += 1
count += 1
elif user_input<0:
total += user_input
negative_number += 1
count += 1
if count==0:
print("You didn't enter any number, code ended")
else:
average = total / count
print("\nThe number of positives:", positive_number)
print("The number of negatives:", negative_number)
print("The total amount of numbers used:", count)
print("The average is", format(average,".2f"), "which is", str(total), "/", str(count))
First, the first if statement is redundant as you test for user_input != 0 as the loop condition. Second, the reason it was going wrong was because on your first input you immediately overwrote the value of user_input, so I put the reprompt code at the end of the loop. Finally, I cleaned up the if elif else statement as this does the exact same with fewer characters. The print statement for the closing line is also executed once we pull out of the loop - sinc eby definition that means user_input == 0
positive_number = 0
negative_number = 0
average = 0
count = 0
new_number = 0
user_input = eval(input("Enter enter as many integers as you want, 0 will halt: "))
while user_input != 0:
if user_input > 0:
new_number += user_input
positive_number += 1
count += 1
else:
new_number += user_input
negative_number += 1
count += 1
average = (new_number / count)
print("\nThe number of positives:", positive_number)
print("The number of negatives:", negative_number)
print("The total amount of numbers used:", count)
print("The average is", format(average,".2f"), "which is", str(new_number), "/", str(count))
user_input = eval(input("Enter enter as many intergers as you want, 0 will halt: "))
print("You didn't enter any number, code ended")
Like it was said in the comments, your first input is getting ignored. Here is an alternative that should work. I excluded a few redundant check statements.
positive_number = 0
negative_number = 0
average = 0
count = 0
new_number = 0
user_input = 1
while user_input != 0:
user_input = eval(input("Enter enter as many integers as you want, 0 will halt: "))
if user_input == 0:
print("You didn't enter any number, code ended")
elif user_input > 0:
new_number += user_input
positive_number += 1
count += 1
else:
new_number += user_input
negative_number += 1
count += 1
average = (new_number / count)
print("\nThe number of positives:", positive_number)
print("The number of negatives:", negative_number)
print("The total amount of numbers used:", count)
print("The average is", format(average,".2f"), "which is", str(new_number), "/", str(count))
There are a number of issues with your code. First of all, the first number that the user prompts is not being evaluated by the code; it's being overwritten once you get to the while loop. There are multiple ways to fix this, but the best would be along the lines:
cont = True
while cont is True:
user_input = int(input("Prompt user"))
if user_input == 0:
cont = False
You could do a break statement too, it doesn't matter.
So that takes care of why the first number isn't being read, and why the code thinks there were only 3 inputs (as well as your count being off). Now what about the two negatives? I don't know why you got that. When I inputted the numbers you listed, I got one negative and two positives. Try it again and see if it works now, I suspect you must've mistyped.
For a python assignment I need to ask users to input numbers until they enter a negative number. So far I have:
print("Enter a negative number to end.")
number = input("Enter a number: ")
number = int(number)
import math
while number >= 0:
numberagain = input("Enter a number: ")
numberagain = int(numberagain)
while numberagain < 0:
break
how do I add up the number of times the user entered a value
i = 0
while True:
i += 1
n = input('Enter a number: ')
if n[1:].isdigit() and n[0] == '-':
break
print(i)
The str.isdigit() function is very useful for checking if an input is a number. This can prevent errors occurring from attempting to convert, say 'foo' into an int.
import itertools
print('Enter a negative number to end.')
for i in itertools.count():
text = input('Enter a number: ')
try:
n = int(text)
except ValueError:
continue
if n < 0:
print('Negative number {} entered after {} previous attempts'.format(n, i))
break
The solution above should be robust to weird inputs such as trailing whitespace and non-numeric stuff.
Here's a quick demo:
wim#wim-desktop:~$ python /tmp/spam.py
Enter a negative number to end.
Enter a number: 1
Enter a number: 2
Enter a number: foo123
Enter a number: i am a potato
Enter a number: -7
Negative number -7 entered after 4 previous attempts
wim#wim-desktop:~$