I want to check if the input is a number(float with 0,one or two decimals) and greater than 0
def getnumber():
print ( "write a number: \n")
isValid = False
while not isValid:
try:
number = float(raw_input().replace(",","."))
if number >= 0:
isValid=True
else:
print ("Number not valid")
isValid = False
getnumber()
except:
print ("Number not valid")
return number
I have the following problems:
1- I don't know how to check if there are only two decimals
2- The code doesn't return the number if first I introduce a negative number
Does anyone know how to fix it?
Thanks a lot
The reason why your code isn't working with negative numbers is because the function calls itself recursively when the number is negative, but the value of isValid is always false after that call, so the loop repeats.
There isn't really any need for the Boolean variable.
That leaves you with the issue of detecting two decimal places. In order to be able to do that at string level you would have to retain the string that you converted to a floating-point number. Supposing you store it as s you could use some test like len(s) > 3 and s[-3] == '.'` to verify it.
This would give you a solution like:
def getnumber():
while True:
try:
s = raw_input("Write a number:").replace(",",".")
number = float(s)
if number >= 0 and len(s) > 3 and s[-3] ==".":
return number
else:
print("Negative or not two decimal places")
except Exception:
print("Invalid number")
print(getnumber())
Related
For an assignment for class, I am needing to create a program that returns if a number is even or odd, while having the main function get user input and displays the output, while another function checks whether the number is even or odd. My python knowledge so far is very basic.
Here is what I've got so far.
def check(number):
if (number % 2) == 0:
return True
else:
return False
def main():
number = int(input("Enter an integer: "))
if check is True:
print("This is an even number.")
elif check is False:
print("This is an odd number.")
__name__ == "__main__"
main()
When I run the code, I get the input prompt, but nothing in return after.
check is a function, so it should be like
if check(number):
print("This is an even number.")
else:
print("This is an odd number.")
Python is very flexible, you don't even need a function.
I would take advantage of f-strings and a ternary:
number = int(input("Enter an integer: "))
print(f'This is an {"odd" if (number % 2) else "even"} number')
Example:
Enter an integer: 2
This is an even number
Enter an integer: 3
This is an odd number
As you are basic this is not the best function for check using bool.
def check(num):
return num % 2 == 0 # return True if even otherwise odd
This code is simple and easily to read rapidly.
This is all the further i've gotten.
import math
num_to_convert = int(input("Please enter any intger from 1 and 100:"))
while num_to_convert < 1 or num_to_convert > 100:
num_to_convert = int(input("Sorry that's not an integer from 1 to 100, try again:"))
else:
print("I'm lost!")
I found this but I don't understand whats going on. Maybe some explanation of what's going on would help.
def decimalToBinary(n):
if(n > 1):
# divide with integral result
# (discard remainder)
decimalToBinary(n//2)
print(n%2, end=' ')
It seems like you want to convert an integer which is not a decimal to binary from your code i would write
while True:
try:
value1=input("Integer you want to convert to binary: ")
binaryvalue=(bin(int(value1)))
print (binaryvalue[2:])
except:
print("I did not understand that")
pass
Valuetoconvert=int(input("Number to convert: "))
u = format(Valuetoconvert, "08b")
print(u)
Try this then
See Below:
def toBin(n):
if n < 2:
return str(n)
else:
if n % 2 == 0:
return toBin(n//2) + "0"
else:
return toBin(n//2) + "1"
Explanation:
This is my sollution which works similar to yours. I hope you know what recursion is otherwise this is going to be difficult to understand.
Anyway the algorithm is to devide the number repeatedly by 2 until the number is smaller than 2 cause then you have the sollution right away(base case).
When the current number is greater than 2 you check wether it is
divisible by 2. If it is even you append a 0 to your string else append a 1. You can try this out on paper to better understand it.
I'm very new to python, in fact, to programming in general. I'm trying to do a program that compares three numbers and determines which one is smaller. I got the code done, but now i need to make it only accept numbers, and still running when it finds a literal value. For example, code will be ok if you put any number, but when you type a string value it crashes. here is the code
num1=0;
num2=0;
num3=0;
num1=int((raw_input("Type below the first number \n")));
num2=int((raw_input("Type below the second number\n")));
num3=int((raw_input("Type below the third number \n")));
if (num1<num2) and (num1<num3):
print "%i is the smallest number of all three"% num1;
elif (num2<num1) and (num2<num3):
print "%i is the smallest number of all three"% num2;
elif (num3<num2) and (num3<num1):
print "%i is the smallest number of all three"% num3;
elif (num1==num2) or (num1==num3) or (num2==num3):
print "Two equal numbers have been written.";
A simple while loop. You may put this in a function.
while True:
try:
num1=int((raw_input("Type below the first number \n")))
break
except ValueError: # catch the *specific* exception
print("Enter numbers only")
Read more on exceptions:
Handling Exceptions in Python
The most important point is probably to separate concerns, ie. keeping user input separate from validation. You've gotten a couple of good solutions using exceptions. Here is a solution that manually validates the input:
def is_int(strval):
"""A string represents an int if all characters are digits.
Returns True if strval represents a valid int, otherwise False.
"""
for ch in strval:
if not ch.isdigit(): # if '0' <= ch <= '9':
return False
return True
def read_int(prompt='Type number: '):
"""Read one integer from user.
"""
while True:
val = raw_input(prompt)
if is_int(val):
return int(val, 10) # the 10 is the radix (base)
else:
print 'That is not a number.., try again'
numbers = []
for pos in 'first', 'second', 'third':
numbers.append(read_int('Type %s number: ' % pos))
to use the exception handling code, all you have to do is change is_int:
def is_int(strval):
try:
int(strval, 10)
except ValueError:
# int() raised an exception, so strval is not an int
return False
else:
# int() didn't raise an exception, so it is an int
return True
it is also possible to be a bit more concise when finding the smallest:
def smallest(a, b, c):
if b > a < c: # if a is less than both b and c..
return a
if a > b < c:
return b
if a > c < b:
return c
return "Error: two of the numbers must be equal!"
you can call it like so:
smallest(numbers[0], numbers[1], numbers[2])
but Python has a shorthand that does exactly that which looks like:
smallest(*numbers)
def getNumber(i):
try:
num = int(raw_input("type in number %s : " %i))
return num
except Exception as e:
print('This is not a valid number')
return getNumber(i)
numbers = []
for i in range(1,4):
numbers.append(getNumber(i))
print(numbers)
You can simply add the input getting code in try except block and handle the ValueError exception with some meaningful code.
try:
num1=int((raw_input("Type below the first number \n")));
num2=int((raw_input("Type below the second number\n")));
num3=int((raw_input("Type below the third number \n")));
except ValueError:
print "Please enter integer only."
exit(-1)
Objective: * Write a python program that repeatedly prompts for input of a positive number until the sum of the numbers is greater than 179. Use at least three modules/functions in your solution.
* The largest number entered cannot exceed 42.
* When the sum of the numbers exceeds 179, print the sum of the numbers, the largest number entered and smallest number entered.
I just need some guidance, specifically for the "input_numbers" module. There must be an easier way to do this than to make a variable for each number. The code is not complete. I haven't even started on the two other modules yet. Thanks in advance.
def input_numbers():
while True:
num1 = raw_input("Enter a positive integer no greater than 42 ")
if num1 <= 0:
print "That is not a positive integer. Try again "
elif num1 > 42:
print "The number cannot exceed 42. Try again "
num2 = raw_input("Enter another positive integer ")
if num2 <= 0:
print "That is not a positive integer. Try again "
elif num2 > 42:
print "The number cannot exceed 42. Try again "
num3 = raw_input("Enter another positive integer ")
if num3 <= 0:
print "That is not a positive integer. Try again "
elif num3 > 42:
print "The number cannot exceed 42. Try again "
num4 = raw_input("Enter another positive integer ")
if num4 <= 0:
print "That is not a positive integer. Try again "
elif num4 > 42:
print "The number cannot exceed 42. Try again "
num5 = raw_input("Enter another positive integer ")
if num5 <= 0:
print "That is not a positive integer. Try again "
elif num5 > 42:
print "The number cannot exceed 42. Try again "
elif sum(num1, num2, num3, num4, num5) > 179:
print_numbers()
add_numbers()
def add_numbers():
print_numbers()
def print_numbers():
input_numbers()
You can knock out all three function requirements by encapsulating each step of your program. Rather than having your loop inside of a function, we'll let main control the loop, and we'll control the flow by passing data into and out of function calls.
Let's rework your input_numbers() function a bit.
def get_input_number():
num = int(raw_input("Enter a positive integer no greater than 42 "))
if num <= 0 or num > 42:
print "Invalid input. Try again "
get_input_number()
else:
return num
So, instead of having input_numbers control the loop as well as the input handling and validation, we have it do just what its name implies: It asks for input, validates it, and then, if it's good, it returns the value to the caller, but if it's bad, it writes a message, and calls itself again to the user can enter good input.
The next function we'll set up is straight from your list of requirements. From all of the numbers that the user enters, we need to find the biggest one. From the language alone, we can determine that we're looking through a set of numbers, and thus, this is a good place to break out a list. Assuming we store all of the users input in a list, we can then pass that list to a function and perform operations on it, like so.
def get_greatest_number(input_list):
highest = input_list[0]
for i in input_list:
if i > highest:
highest = i
return highest
We set the first element of the list to a variable highest and then check all other elements in the list against that initial value. If we find one that's bigger, we then reassign the highest variable to the element that was bigger. Once we do this for each element in the list, the number inside of highest will now be, just that, the highest number, and so, we'll return it to the main program.
Similarly, we can do the same for finding the smallest.
def get_smallest_number(input_list):
smallest = input_list[0]
for i in input_list:
if i < smallest:
smallest = i
return smallest
Finally, we get to our main loop. Here we declare an empty list, number_list to store all the numbers in. And we use the sum of that as our loop condition.
if __name__ == '__main__':
number_list = []
while sum(number_list) < 179:
number_list.append(get_input_number())
In the body of the loop, we call our get_input_number() and append its result to the list we made. Once the sum of the numbers in the list exceed 179, the while loop will exit and we can finally show the user the results.
print
print '-------------------------'
print 'total of numbers entered: %d' % sum(number_list)
print 'greatest number entered: %d' % get_greatest_number(number_list)
print 'smallest number entered: %d' % get_smallest_number(number_list)
Here we can the get_greatest_number and get_smallest_number we made, and we give them the list of numbers as an argument. They'll loop though the lists, and then return the appropriate values to the print statements.
Yes, of course there's a better way than making a variable for each number. Store them in a list. Storing them in a list also makes finding their sum and the highest and lowest value easy (there are built-in functions for this).
As a further hint, you'll want to use two loops, one inside the other. The outer loop keeps the user entering numbers until their sum exceeds 179. The inner loop keeps the user entering a single number until it's between 1 and 42 inclusive.
def get_int(prompt=''):
while True:
try:
return int(raw_input(prompt))
except ValueError:
pass
def get_values():
values = []
total = 0
while total <= 179:
val = get_int('Enter a positive integer <= 42: ')
if 0 <= val <= 42:
values.append(val)
total += val
return values
def print_info(values):
print 'Sum is {}'.format(sum(values))
print 'Largest value is {}'.format(max(values))
print 'Smallest value is {}'.format(min(values))
def main():
values = get_values()
print_info(values)
if __name__=="__main__":
main()
You can repeatedly poll the number in a loop, and add the inputs into a list, e.g.
def input_numbers():
user_inputs = [] # a list of all user's inputs
while True:
num = raw_input("Enter a positive integer no greater than 42 ")
try:
num = int(num) # convert input string to integer
if num <= 0:
print "That is not a positive integer. Try again "
elif num > 42:
print "The number cannot exceed 42. Try again "
user_inputs.append(num)
except ValueError: # conversion to integer may fail (e.g. int('string') ?)
print 'Not a Number:', num
if some_condition_regarding(user_inputs):
break # eventually break out of infinite while loop
here some well-known tricks:
def min_and_max(your_num_list)
min=your_num_list[0]
max=your_num_list[0]
for num in your_num_list:
if num < min:
min=num
if max > num
max=num
return min,max
When you're writing a standalone Python program, it’s a good practice to use a main function. it allows you to easily add some unit tests, use your functions or classes from other modules (if you import them), etc.
And as others already said, it is a good idea to create a list and append a new element to it each time the user enters a valid number (until the sum of the numbers axceeds 179). If user entered an incorrect value, then just don’t append anything to the list and skip to the next iteration (so the user will be asked to enter a number again).
So basically it could look like this:
def validate_entered_number(num):
"""
Checks if the number is positive and is less or equal to 42.
Returns True if the number matches these conditions,
otherwise it returns False.
"""
if num < 0:
print "That is not a positive integer."
return False
if num > 42:
print "The number cannot exceed 42."
return False
return True
def main():
entered_numbers = []
while True:
try:
num = int(raw_input("Enter a positive integer less or equal to 42: "))
except ValueError:
print "You should enter a number"
continue
if validate_entered_number(num):
entered_numbers.append(num)
if sum(entered_numbers) > 179:
print "The sum of the numbers is %s" % sum(entered_numbers)
print "The smallest number entered is %s" % min(entered_numbers)
print "The largest number entered is %s" % max(entered_numbers)
return
if __name__ == "__main__":
main()
In fact, I can imagine a situation where you would want to just store the sum of the numbers, the smallest number and the largest number in three variables and update these variables in each iteration (add current number to the sum and compare it to the currently known smallest and larger numbers and update the corresponding variables when necessary), but in this case the longest list you can possibly have is only 180 elements (if all numbers are 1 and the user doesn’t enter 0 or you have modified the program to deny entering 0), which is very small amount of elements for a list in Python. But if you had to deal with really big amounts of numbers, I’d recommend to switch to a solution like this.
Thanks to everyone who answered. I've written the following code and it works nearly perfectly except the last module. If you exit the program after the first run (by pressing 0) it will exit, but if you run it a second time pressing 0 won't make it exit. It'll just go back to the beginning of the program. I don't know why.
Note: The assignment has various requirements that I had to incorporate in my code. Hence the unnecessary modules, global variables, and comments.
maxNum = 42 # declares global variable maxNum
target = 179 # declares global variable target
def user_input(): # prompts user to input a number 42 or less until all add up to 179
x = 0
nums = []
while sum(nums) <= target:
nums.append(int(raw_input("Enter a number: ")))
if int(nums[x]) > int(maxNum):
print "Number cannot exceed 42."
user_input()
else:
x += 1
print_nums(nums,x)
def print_nums(nums,x): # prints the sum of the numbers, the smallest, and the largest
print "Sum of all numbers is", sum(nums)
nums.sort()
x -= 1
print "Largest number entered is", nums[x]
print "Smallest number entered is", nums[0]
decide()
def decide(): # allows user to continue the program or exit
exit = raw_input("<9 to enter a new set of number. 0 to exit.> ")
while True:
if int(exit) == 0:
return
elif int(exit) == 9:
user_input()
user_input()
The following code is my attempt at simulating a lottery.
import random
def lottery(numbers):
lottoNumbers = [randint('0,100') for count in range(3)]
if numbers == lottoNumbers:
print('YOU WIN $10,000')
else:
print('YOU LOSE,DUN DUN DUNNN!')
return numbers
def main():
numbers = int(input('Enter a number: '))
if numbers == lottoNumbers:
numbers = lottery(numbers)
else:
numbers = lottery(numbers)
main()
Hey guys I've gotten this far with the help you've given me. I'm trying to write the code so that 3 lotto numbers at random will be chosen. Then the user must enter 3 of his/her own lotto numbers. If they get all 3 correct then they win the whole prize, if they get the 3 numbers but not in the correct order they win some of the prize. Obviously if they guess all wrong then a print statement would state that. What I'm confused about is how can I write the code so that the user can enter 3 numbers to try matching the random lottery numbers. I also want to print the 3 lottery numbers after the user inputs his/her choices. Any ideas guys?
Thanks for your help everyone.
You seem a bit confused about what the role of the arguments in a function are. You've said that your randm function takes the argument "number", but then you haven't actually used it anywhere. The next time number appears, you've assigned it a completely new value, so any value passed to randm isn't actually being used.
Also, the function is trying to return x, when x hasn't been assigned within the function. Either you already have a global variable called x already defined, in which case the function will just return that variable, or the function will just fail because it can't find the variable x.
Here's a quick example I've done where you pass their three numbers as a list as an argument to the function.
import random
theirNumbers=[5,24,67]
def checkNumbers(theirNumbers):
lottoNumbers = []
for count in range(3)
lottoNumbers.append(random.randint(0,100))
winning = True
for number in theirNumbers:
if not each in lottoNumbers: winning=False
if winning == True: print("Winner!")
There are a few things wrong with your implementation, to name a few:
if you are trying to compare the output of the function randm to x, you will need to include a return value in the function, like so:
def randm():
return return_value
You appear to be printing all the values but not storing them, in the end you will only end up with the final one, you should attempt to store them in a list like so:
list_name = [randint(0,100) for x in range(x)]
This will generate randint(0,100) x times in a list, which will allow you to access all the values later.
To fix up your code as close to what you were attempting as possible I would do:
import random
def randm(user_numbers):
number = []
for count in range(3):
number.append(random.randint(0, 100))
print(number)
return user_numbers == number
if randm(x):
print('WINNER')
If you are looking for a very pythonic way of doing this task,
you might want to try something like this:
from random import randint
def doLotto(numbers):
# make the lotto number list
lottoNumbers = [randint(0,100) for x in range(len(numbers))]
# check to see if the numbers were equal to the lotto numbers
if numbers == lottoNumbers:
print("You are WinRar!")
else:
print("You Lose!")
I'm assuming from your code (the print() specifically) that you are using python 3.x+
Try to post your whole code. Also mind the indentation when posting, there it looks like the definition of your function would be empty.
I'd do it like this:
import random
def lottery():
win = True
for i in range(3):
guess = random.randint(1,100)
if int(raw_input("Please enter a number...")) != guess:
win = False
break
return win
Let so do this in few steps.
First thing you should learn in writing code is to let separate pieces of code( functions or objects) do different jobs.
First lets create function to make lottery:
def makeLottery(slotCount, maxNumber):
return tuple(random.randint(1,maxNumber) for slot in range(slotCount))
Next lets create function to ask user's guess:
def askGuess(slotCount, maxNumber):
print("take a guess, write {count} numbers separated by space from 1 to {max}".format(count = self.slotCount, max = self.maxNumber))
while True: #we will ask user until he enter sumething suitable
userInput = raw_input()
try:
numbers = parseGuess(userInput,slotCount,maxNumber)
except ValueError as err:
print("please ensure your are entering integer decimal numbers separated by space")
except GuessError as err:
if err.wrongCount: print("please enter exactly {count} numbers".format(count = slotCount))
if err.notInRange: print("all number must be in range from 1 to {max}".format(max = maxNumber))
return numbers
here we are using another function and custom exception class, lets create them:
def parseGuess(userInput, slotCount,maxNumber):
numbers = tuple(map(int,userInput.split()))
if len(numbers) != slotCount : raise GuessError(wrongCount = True)
for number in numbers:
if not 1 <= number <= maxNumber : raise GuessError(notInRange = True)
return numbers
class GuessError(Exception):
def __init__(self,wrongCount = False, notInRange = False):
super(GuessError,self).__init__()
self.wrongCount = wrongCount
self.notInRange = notInRange
and finally function to check solution and conratulate user if he will win:
def checkGuess(lottery,userGuess):
if lottery == userGuess : print "BINGO!!!!"
else : print "Sorry, you lost"
As you can see many functions here uses common data to work. So it should suggest you to collect whole code in single class, let's do it:
class Lottery(object):
def __init__(self, slotCount, maxNumber):
self.slotCount = slotCount
self.maxNumber = maxNumber
self.lottery = tuple(random.randint(1,maxNumber) for slot in range(slotCount))
def askGuess(self):
print("take a guess, write {count} numbers separated by space from 1 to {max}".format(count = self.slotCount, max = self.maxNumber))
while True: #we will ask user until he enter sumething suitable
userInput = raw_input()
try:
numbers = self.parseGuess(userInput)
except ValueError as err:
print("please ensure your are entering integer decimal numbers separated by space")
continue
except GuessError as err:
if err.wrongCount: print("please enter exactly {count} numbers".format(count = self.slotCount))
if err.notInRange: print("all number must be in range from 1 to {max}".format(max = self.maxNumber))
continue
return numbers
def parseGuess(self,userInput):
numbers = tuple(map(int,userInput.split()))
if len(numbers) != self.slotCount : raise GuessError(wrongCount = True)
for number in numbers:
if not 1 <= number <= self.maxNumber : raise GuessError(notInRange = True)
return numbers
def askAndCheck(self):
userGuess = self.askGuess()
if self.lottery == userGuess : print "BINGO!!!!"
else : print "Sorry, you lost"
finally lets check how it works:
>>> lottery = Lottery(3,100)
>>> lottery.askAndCheck()
take a guess, write 3 numbers separated by space from 1 to 100
3
please enter exactly 3 numbers
1 10 1000
all number must be in range from 1 to 100
1 .123 asd
please ensure your are entering integer decimal numbers separated by space
1 2 3
Sorry, you lost
>>> lottery = Lottery(5,1)
>>> lottery.askAndCheck()
take a guess, write 5 numbers separated by space from 1 to 1
1 1 1 1 1
BINGO!!!!