Clamp

限制范围

≈ 15 min · python-functions python-conditionals · Open in WolfCode

The smallest useful function with multiple parameters. Every UI slider, audio mixer, and game has this.

The problem

Return value confined to [lo, hi]. Below range → return lo. Above → return hi. Inside → return value.

The pattern

Python · runnable

def clamp(value, lo, hi):
    if value < lo:
        return lo
    elif value > hi:
        return hi
    else:
        return value

for v in [5, -3, 99, 0, 10, -5]:
    print(f"clamp({v:>3}, 0, 10) = {clamp(v, 0, 10)}")

Loading Python runtime (~5 MB, one-time)…

Early-return form (also fine)

return exits the function — no else needed

def clamp(value, lo, hi):
    if value < lo:
        return lo
    if value > hi:
        return hi
    return value         # only reached if neither earlier return fired

print(clamp(5, 0, 10), clamp(-3, 0, 10), clamp(99, 0, 10))

Loading Python runtime (~5 MB, one-time)…

Check yourself

clamp(5, 0, 10) — what does this return?

Now you try

Open 01-clamp.py. 6 tests including both boundaries and a negative-range case.