定义包含不等式的函数

Question

I want to make a define a function f(x,t) such that f(x,t) = 1 when 0.1 <= x <= 0.3 , and it is 0 otherwise.

I wasn't sure how to do this with the normal def command in python. I was trying to add elif statement in the definition but it's not working out for me.

Answer 1

You could use an if statement inside the function:

def f(x,t):
    if 0.1 <= x <= 0.3:
        return 1
    return 0

or, more elegantly, you could just convert the boolean expression to an int , since True will become 1 and False will become 0 :

def f(x,t):
    return int(0.1 <= x <= 0.3)

Also note that since the return value depends only on x , you can remove t from the function's definition.

Answer 2

def f(x, t):
    return 1 if 0.1 <= x <= 0.3 else 0

Answer 3

I don't see why you need elif here. You can define the condition as 0.1 <= x <= 0.3 , and since a True maps to 1 and False to 0 if you call int(..) , you can define this as:

def f(x, t):
    return int(0.1 <= x <= 0.3)

But I think it makes sense to return a bool anyway. A bool is after all a subclass of int , and both 1 == True and 0 == False hold.