Python - Ensuring a Variable Holds a Positive Number

Python - Ensuring a variable holds a positive number

I am unclear as to what you want to do -- either the variables can be negative, or they can't.

If you are decrementing a variable repeatedly and after doing so you want to check whether they are negative, do so with an if -- that's what it's for!
```
if value < 0: # do stuff
```
If you think the variables should never be negative and you want to assert this fact in the code in the code, you do
```
assert value > 0
```
which may raise an AssertionError if the condition doesn't hold (assert will not execute when Python is not run in debug mode).
If you want the variable to be 0 if it has been decreased below 0, do
```
value = max(value, 0)
```
If you want the variable to be negated if it is negative, do
```
value = value if value > 0 else -value
```
or
```
value = abs(value)
```

Creating a loop to check a variable to make sure it is a positive integer

To expand a bit on what the others have given you:

n = -1
while n < 0:
    try:
        n = int(input("Please enter the number of Fibonacci numbers you want: "))
    except ValueError:
        continue

Which will handle users who try to sneakily put in values like HELLO instead of 5

If-Else Statement-Positive and Negative Integers

On the first 3 lines, you collect a number, but always into the same variable (num). Since you don't look at the value of num in between, the first two collected values are discarded.

You should look into using a loop, e.g. for n in range(3):

for n in range(3):
    num = int(input("Enter a number: "))
    if num > 0:
        print("YES")
    else:
        print("NO")

Python numpy.random.normal only positive values

The normal distribution, by definition, extends from -inf to +inf so what you are asking for doesn't make sense mathematically.

You can take a normal distribution and take the absolute value to "clip" to positive values, or just discard negative values, but you should understand that it will no longer be a normal distribution.

Python - Ensuring a Variable Holds a Positive Number