I am working on a function that sums up the amount of positive and negative numbers a user inputs. It has to be in a loop and has to have two functions(on for pos, one for neg) to return True or False. I have tried everything and am so lost and don't even know where to start anymore. This is what I have so far:
pos = 0
neg = 0
num = int(input("Please enter a positive or negative number. Or 0 to quit"))
while num > -100 or num < 100:
num = int(input("Please enter a positive or negative number. Or 0 to quit"))
if num > 100 or num < -100:
print("Please only enter integers between -100 to 100")
num = int(input("Please enter a positive or negative number. Or 0 to quit"))
elif num == 0:
print("Here is your summary: ")
print("You entered: ", pos, "positives number(s) and", neg, "negative number(s)")
def if_positive(pos):
if num > 0:
pos = pos + 1
def if_negative(neg):
if num < 0:
neg = neg + 1
if_positive(pos)
if_negative(neg)
Every time I try something, I get one part correct and then the other wrong. Python for Everybody hasn't helped at all and I've done hours of research and nothing helps. Please help me. Every time I post a question on here it gets removed! I have no idea what I'm doing wrong, I am just trying to ask a simple question :( So I will try for the third time!
Lets do it as follow
Lets have while loop then if the num is zero just break it otherwise check the conditions
I have added two lists but if you just count how many numbers positive and negative then you don't need lists you can use integer count variables
postive_numbers =[]
negative_numbers =[]
while True:
num = int(input("Please enter a positive or negative number. Or 0 to quit\n Enter the number: "))
if num>100 or num < -100:
print("Please only enter integers between -100 to 100")
continue
if num == 0:
print("Here is your summary:\n ")
print("You entered: \npositives number(s) {} \nnegative number(s){} ".format(len(postive_numbers),len(negative_numbers)))
break
elif num< 0:
negative_numbers.append(num)
else:
postive_numbers.append(num)
If I had to guess, I'd say your questions are being removed because they sound like school assignments, and people tend to sour a little at the idea of people going to StackOverflow to have others do their homework for them. That said, it seems to me like you've put in a good-faith effort based on what you've already written, and there's nothing wrong with asking for help when you don't understand something after trying to figure it out yourself.
Try this:
def is_positive(number):
"""
This could be shortened to simply:
`return number > 0`
"""
if number > 0:
return True
else:
return False
def is_negative(number):
"""
Similarly, this could be shortened to:
`return number < 0`
"""
if number < 0:
return True
else:
return False
n_positive = 0
n_negative = 0
while True:
num_entered = int(input("Please enter a positive or negative number. Or 0 to quit"))
if not -100 < num_entered < 100:
print("Please only enter integers between -100 to 100")
elif is_positive(num_entered):
# this is a shortcut for `n_positive = n_positive + 1`
n_positive += 1
elif is_negative(num_entered):
n_negative += 1
else:
break
print("Here is your summary:")
# this is equivalent to what you had in your question, but uses "f-strings",
# which were implemented in Python 3.6 and are super convenient
print(f"You entered {n_positive} positive number(s) and {n_negative} negative number(s)")
A few extra notes you might find helpful:
if not -100 < num_entered < 100: is equivalent to if num > 100 or num < -100:, but just a cleaner way of writing it
while True is an idiom in Python that essentially means "keep looping forever until I break out of it or exit the program." From the code you had written, it seems like you want to keep allowing the user to input numbers until they enter "0 to quit". That's the condition upon which you want to break out of the loop.
"def" itself isn't a function -- def is a keyword that defines a function, which is a snippet of code that performs a single task that can be re-used later. You said your two functions needed to return True or False. In Python, the return keyword causes a function to exit and "return" the value specified.
This is why you're able to use those pre-defined functions directly in the the if and elif statements later. You can think of the way "if" works as taking the code between if and : and evaluating it. If it evaluates to True, then the block of code inside (i.e., indented under) the if statement is executed and any elif or else statements you may or may not have after that are skipped. Or, if it evaluates to False, then Python "moves on," and if you have an elif statement after the if, it repeats the same process there. Finally, if neither or if or elif blocks evaluate to True and you have an else block, that code is run.
This is a very long way of saying that in your case, the logical flow is: "if the number isn't between -100 and 100, remind the user of the acceptable range of values. Otherwise, if the number is_positive, add 1 to the running count of positive numbers entered. Or, if the number is_negative, add 1 to the count of negative numbers. Otherwise, the only remaining possibility is that the number is 0, so the user is finished entering numbers and we should break out of the loop and show them their summary.
Hope this helps! Feel free to comment with any other questions you have.
Related
To begin, a definition:
A polydivisible number is an integer number where the first n digits of the number (from left to right) is perfectly divisible by n. For example, the integer 141 is polydivisible since:
1 % 1 == 0
14 % 2 == 0
141 % 3 == 0
I'm working on a recursive polydivisible checker, which, given a number, will check to see if that number is polydivisible, and if not, recursively check every other number after until it reaches a number that is polydivisible.
Unfortunately, my code doesn't work the way I want it to. Interestingly, when I input a number that is already polydivisible, it does its job and outputs that polydivisible number. The problem occurs when I input a non-polydivisible number, such as 13. The next polydivisible number should be 14, yet the program fails to output it. Instead, it gets stuck in an infinite loop until the memory runs out.
Here's the code I have:
def next_polydiv(num):
number = str(num)
if num >= 0:
i = 1
print(i)
while i <= len(number):
if int(number[:i]) % i == 0:
i += 1
print(i)
else:
i = 1
print(i)
num += 1
print(num)
else:
return num
else:
print("Number must be non-negative")
return None
I'm assuming the problem occurs in the else statement inside the while loop, where, if the number fails to be polydivisible, the program resets i to 0, and adds 1 to the original number so it can start checking the new number. However, like I explained, it doesn't work the way I want it to.
Any idea what might be wrong with the code, and how to make sure it stops and outputs the correct polydivisible number when it reaches one (like 14)?
(Also note that this checker is only supposed to accept non-negative numbers, hence the initial if conditional)
The mistake is that you are no updating number after incrementing num.
Here is working code:
def next_polydiv(num):
number = str(num)
if num >= 0:
i = 1
print(i)
while i <= len(number):
if int(number[:i]) % i == 0:
i += 1
print(i)
else:
i = 1
print(i)
num += 1
print(num)
number = str(num) # added line
else:
return num
else:
print("Number must be non-negative")
return None
I have a similar answer to #PranavaGande, the reason is I did not find any way to iterate an Int. Probably because there isn't one...Duh !!!
def is_polydivisible(n):
str_n = str(n)
list_2 = []
for i in range(len(str_n)):
list_2.append(len(str_n[:i+1]))
print(list_2)
list_1 = []
new_n = 0
for i in range(len(str_n)):
new_n = int(str_n[:i+1])
list_1.append(new_n)
print(list_1)
products_of_lists = []
for n1, n2 in zip(list_1, list_2):
products_of_lists.append(n1 % n2)
print(products_of_lists)
for val in products_of_lists:
if val != 0:
return False
return True
Now, I apologise for this many lines of code as it has to be smaller. However every integer has to be split individually and then divided by its index [Starting from 1 not 0]. Therefore I found it easier to list both of them and divide them index wise.
There is much shorter code than mine, however I hope this serves the purpose to find if the number is Polydivisible or Not. Of-Course you can tweak the code to find the values, where the quotient goes into decimals, returning a remainder which is Non-zero.
while True:
numbers = input('> ')
if numbers == 'done':
break
total = 0
for number in numbers:
if numbers == int:
total = total + numbers
print(total)
I've had a hard time understanding exactley what u want to do with this code, please use a proper code block next time, with proper indentation. My guess is that u want to get a input number like 345 and add 3+4+5 as a output. If the input is not a int it should break the loop. Ive come up with 2 diffrent solutions, depending on what you need.
This code will simply take the input and check if it is "done", if it is not "done" it will try to add. This is a easy to understand solution but it will produce a error if the input is any diffrent string than "done".
while True:
numbers = input(">")
if numbers == "done":
break
else:
total = 0
for number in numbers:
total += int(number)
print(total)
This approach will test for the "done" string again, but afterwards will also check if the input can be converted into a int. if not the error is captured and it will return "invalid input". If u want the programm to terminate at any string u can just put break in the except section.
while True:
numbers = input(">")
if numbers == "done":
break
else:
try:
testing = int(numbers)
total = 0
for number in numbers:
total += int(number)
except:
total = "invalid input"
print(total)
im a Beginner myself and if a experiencend person can show me a better way to do this i would be very interested
while True:
numbers = input('> ')
if numbers == 'done':
break
total = 0
for number in numbers:
if numbers == int:
total = total + numbers
print(total)
Assuming this as your code:
Here's a solution to your problem-->
numbers=[]
while True:
a=input('>')
if a=='done':
break
else:
numbers.append(a)
total=0
for number in numbers:
total = total + int(number)
print(total)
By default everything gets accepted as string so we convert it to integer to find total.
Also we use list to store all the values we accept.
Another Solution is-->
numbers=[]
while True:
a=input('>')
if a=='done':
break
else:
numbers.append(a)
p=map(int,numbers)
print(sum(p))
Hope you understand the solution :-)
total = 0
average = 0
count = 0
while True:
numbers = input('> ')
if numbers == 'done': break
try:
total = int(numbers) + total
count = count + 1
except:
print('nope')
try:
average = total / count
except:
print('error')
print(total)
print(average)
print(count)
Try this:
total = 0
number_of_inputs = 0
while True:
number_string = input('Enter a number: ')
try:
total += float(number_string)
number_of_inputs += 1
except ValueError:
break # we weren't given a number, so exit the loop
# Now that we're outside of the loop, print out the total:
print('The total is:', total)
if number_of_inputs > 0:
average = total / number_of_inputs
print('The average is:', average)
else:
print('The average cannot be calculated, as no inputs were given.')
Do you see what's happening? The while loop keeps ask for and adding integers to total until a non-integer (like "done") is given. Once it gets that non-integer, the int() function will fail, and the exception it throws will get caught, and the code will immediately break out of the while loop.
And once out of the loop, the total and the average are printed out.
A few things you should be aware of:
If the user gave no inputs (which is possible here), the total will correctly print out as 0, but if you try to calculate the average, you will error, due to diving by number_of_inputs (which is also 0). That is why I check that number_of_inputs is greater than zero before I even attempt to calculate the average.
Originally I used int() to convert the string to a number, but I changed it to use float() instead. I figure that since you want to calculate an average, averages are not necessarily integers (even if all the inputs are), so there's no point in enforcing integer input. That is why I changed the int() to float(), but whether or not you want to use it is up to you.
ValueError isn't a function; it's an Exception. At this point you probably don't know what Exceptions are, so just know that they are special cases that can happen, and they're often used for catching errors, such as bad input values.
In the code I posted above, the loop is always expecting numerical input. But as soon as we have input that can't be converted to a number, the program then says, "Hey, I have an exception to what we're expecting! The exception is that there's an error in the value!" Then the program, instead of continuing to the next line of code (which is number_of_inputs += 1) will then execute the block of code under the except ValueError: section. And in the code above, all it does is call break, which exits the loop.
Once out of the loop, the code prints out the total and the average.
If it weren't for the try: and except ValueError: lines in the code, then the program would abruptly end (with a lengthy error message) once someone gave a non-numerical input. That happens because the call to float() wouldn't know how to convert a value like "done" to a number, so it does nothing more than just quitting.
However, by using try: and except ValueError:, we are anticipating that someone might give non-numerical input. When that happens (which it will, when the user is finished giving inputs) -- instead of quitting -- we want an alternate action to take. And we specify that alternate action to be a simple break out of the loop -- which will allow the program to continue with whatever is after the loop.
I hope this makes sense. If it doesn't, it will make more sense once you start learning about Exceptions in Python.
Apologies if similar questions have been asked but I wasn't able to find anything to fix my issue. I've written a simple piece of code for the Collatz Sequence in Python which seems to work fine for even numbers but gets stuck in an infinite loop when an odd number is enter.
I've not been able to figure out why this is or a way of breaking out of this loop so any help would be greatly appreciate.
print ('Enter a positive integer')
number = (int(input()))
def collatz(number):
while number !=1:
if number % 2 == 0:
number = number/2
print (number)
collatz(number)
elif number % 2 == 1:
number = 3*number+1
print (number)
collatz(number)
collatz(number)
Your function lacks any return statements, so by default it returns None. You might possibly wish to define the function so it returns how many steps away from 1 the input number is. You might even choose to cache such results.
You seem to want to make a recursive call, yet you also use a while loop. Pick one or the other.
When recursing, you don't have to reassign a variable, you could choose to put the expression into the call, like this:
if number % 2 == 0:
collatz(number / 2)
elif ...
This brings us the crux of the matter. In the course of recursing, you have created many stack frames, each having its own private variable named number and containing distinct values. You are confusing yourself by changing number in the current stack frame, and copying it to the next level frame when you make a recursive call. In the even case this works out for your termination clause, but not in the odd case. You would have been better off with just a while loop and no recursion at all.
You may find that http://pythontutor.com/ helps you understand what is happening.
A power-of-two input will terminate, but you'll see it takes pretty long to pop those extra frames from the stack.
I have simplified the code required to find how many steps it takes for a number to get to zero following the Collatz Conjecture Theory.
def collatz():
steps = 0
sample = int(input('Enter number: '))
y = sample
while sample != 1:
if sample % 2 == 0:
sample = sample // 2
steps += 1
else:
sample = (sample*3)+1
steps += 1
print('\n')
print('Took '+ str(steps)+' steps to get '+ str(y)+' down to 1.')
collatz()
Hope this helps!
Hereafter is my code snippet and it worked perfectly
#!/usr/bin/python
def collatz(i):
if i % 2 == 0:
n = i // 2
print n
if n != 1:
collatz(n)
elif i % 2 == 1:
n = 3 * i + 1
print n
if n != 1:
collatz(n)
try:
i = int(raw_input("Enter number:\n"))
collatz(i)
except ValueError:
print "Error: You Must enter integer"
Here is my interpretation of the assignment, this handles negative numbers and repeated non-integer inputs use cases as well. Without nesting your code in a while True loop, the code will fail on repeated non-integer use-cases.
def collatz(number):
if number % 2 == 0:
print(number // 2)
return(number // 2)
elif number % 2 == 1:
result = 3 * number + 1
print(result)
return(result)
# Program starts here.
while True:
try:
# Ask for input
n = input('Please enter a number: ')
# If number is negative or 0, asks for positive and starts over.
if int(n) < 1:
print('Please enter a positive INTEGER!')
continue
#If number is applicable, goes through collatz function.
while n != 1:
n = collatz(int(n))
# If input is a non-integer, asks for a valid integer and starts over.
except ValueError:
print('Please enter a valid INTEGER!')
# General catch all for any other error.
else:
continue
Program has to count positive and negative numbers and compute the average. I feel like i have the right code but maybe something is off. This was done on python idle 3.5. I would appreciate any and all help.
#Variables
total=0
pos=0
neg=0
avg=0
i=eval(input("Enter an integer, the input ends if it is 0:"))
#main
while (i!=0):
total=total+i
i=eval(input("Enter an integer, the input ends if it is 0:"))
if(i>0):
pos+=1
elif(i<0):
neg+=1
print("The number of positives is ", pos)
print("The number of negatives is ", neg)
print("The total is",total)
print("The average is ", avg)
avg=total/(pos+neg)
One Problem your code has is, that the first number you are entering does not count towards either the positive or negative counts in your loop because it is outside of it. As soon as you enter the loop you do add it to the total, but then you ask for the next number. This way your first number is never evaluated.
What you could do is a while loop that has the condition "True", so it runs every time you start the program. The evaluation on whether your input is a zero can be (and in this case must be) handled in your else/elif/else block.
If you don't include a break there you are getting an infinite loop.
You should not us eval(). The Documentation on python states this:
This function can also be used to execute arbitrary code objects (such as those created by compile()). In this case pass a code object instead of a string. If the code object has been compiled with 'exec' as the mode argument, eval()’s return value will be None.
If you use int() the program knows if it is negative or not since you compare the input to zero in your if statements.
Maybe do something like this:
#Variables
total = 0
pos = 0
neg = 0
# avg = 0 (you don't have to declare this variable since you calculate it
# anyway later on)
# removed the input from here since it did not contribute to the pos/neg count
#main
while (True):
# maybe use a while loop with the condition "True" so it runs every time
i = int(input("Enter an integer, the input ends if it is 0: "))
total = total + i
if(i > 0):
# counts 1 up if integer is positive
pos += 1
elif(i < 0):
# counts 1 up if integer is negative
neg += 1
else:
# break out of the loop as soon as none of the above conditions is true
# (since it hits a 0 as input)
# else you get an infinite loop
break
avg = total / (pos + neg)
print("The number of positives is ", pos)
print("The number of negatives is ", neg)
print("The total is ", total)
print("The average is ", avg)
Simple question but it is driving me nuts. why when I run this code does it just keep repeating itself? And my indentations are correct just had to space 4 times to post this for whatever reason.
High Scores
0 - Exit
1 - Show Scores
Source code:
scores = []
choice = None
while choice != "0":
print(
"""
High Scores
0 - Exit
1 - Show Scores
"""
)
choice = input("choice: ")
print()
if choice == "0":
print ("exiting")
elif choice == "1":
score = int(input("what score did you get?: "))
scores.append(score)
else:
print ("no")
input ("\n\nPress enter to exit")
This is because you are not using proper indentation. Please indent the code under the while loop that you want to execute while choice != 0
Further there is no mistake with comparison as #wookie919 wrongly indicated because you're taking a String as input and not an Int. You can however typecast your input as a string by wrapping it around an int() like int(input("Choice .. "))
Hope it helped.
It's because you are comparing an Integer to a String. Try entering "0" instead of just 0. Or modify your program to compare with 0 instead of "0".