Python User Must Only Enter Float Numbers

I am trying to find out how to make it so the user [only enters numbers <0] and [no letters] allowed. Can someone show me how I would set this up. I have tried to set up try/cat

Solution 1:

I think you want numbers only > 0, or do you want less than zero? Anyway to do this you can using try/except, inside a while loop.

For Python 3, which I think you are using?

goodnumber = Falsewhilenot goodnumber:
    try:
        edgeone = int(input('Enter the first edge of the triangle:'))
        if edgeone > 0:
            print('thats a good number, thanks')
            goodnumber = Trueelse:
            print('thats not a number greater than 0, try again please')
    except ValueError:
        print('Thats not a number, try again please')

hope this helps.

Solution 2:

you must use except handler for this case :

try:
    value = int(raw_input("Enter your number:"))
    ifnot ( value < 0 ):
        raise ValueError()
except ValueError:
    print"you must enter a number <0 "else:
    print value #or something else 

Also This question already has an answer here: Accepting only numbers as input in Python

Solution 3:

You can do like this.

i = 1while(type(i)!=float):
    i=input("enter no.")
    try:
        int(i):
    except:
        try:
            i = float(i)
        except:
            passprint(i)