Python 将 function 压缩成字符串

Question

I have a function like so:

def ease_bounce_out(t, bounces=None):
    if bounces is None:
        bounces = [4 / 11, 6 / 11, 8 / 11, 3 / 4, 9 / 11, 10 / 11, 15 / 16, 21 / 22, 63 / 64]

    bounces.insert(0, 1 / bounces[0] / bounces[0])
    if t < bounces[1]:
        return bounces[0] * t * t
    else:
        for i in range(3, len(bounces) - 2, 3):
            if t < bounces[i]:
                t -= bounces[i - 1]
                return bounces[0] * t * t + bounces[i + 1]

    t -= bounces[len(bounces) - 2]
    return bounces[0] * t * t + bounces[len(bounces) - 1]

and I would like to compact it all down into 1 string so that I can use the eval() function to get an output for any value of t . I have an example of an easier function:

def ease_poly(t, power=2):
    t *= 2
    if t < 1:
        return t ** power
    else:
        return 2 - ((2 - t) ** power)

would become:

def ease_poly(power=2):
    return f"(t * 2) ** {power} if (t * 2) < 1 else 2 - ((2 - (t * 2)) ** {power})"

This way, I could use this string and evaluate the function for any value of t by simply doing:

ease = ease_poly(power=3)
t = 0.4  # 0 <= t <= 1
print(eval(ease)) 

Now to get started with my question, it doesn't actually have to be 1 line, this is what I've been thinking of:

def ease_bounce_out(bounces=None):
    if bounces is None:
        bounces = [4 / 11, 6 / 11, 8 / 11, 3 / 4, 9 / 11, 10 / 11, 15 / 16, 21 / 22, 63 / 64]

    return # some code here that compiles the rest into a string

Answer 1

A small tip,

1. bounces[ -1 ] = Last item

   bounces[ -2 ] = Last second item

   Don't use bounces[ len(bounces) - 1 ]

Answer: You can't have that string answer with eval. Because your function is making decisions based on t . You have to pass t.

If evaluating for all t is your primary concern then other way could help. Forget about eval. Don't pass t but use t in function then it will look up in global scope and uses t in that scope.

Example:

This function requires t to be passed.

def mathuer(t, b = 23 ):
    x = t
    if b > t:
        x = t
    return x

This function uses global t.

def mathuer(b = 23 ):
    x = t
    if b > t:
        x = t
    return x

This is how it works,

t = 34
obj = mathuer() // Uses t defined above