Shorten the python if-statement syntax

Question

Is it possible to shorten the if statements below ?

if r < 0: r = 0
elif r > 255: r = 255
if g < 0: g = 0 
elif g > 255: g = 255
if b < 0: b = 0
elif b > 255: b = 255

Answer 1

This is what you call as clamping. Create a clamp function as below:

def clamp(n, smallest, largest): 
 return max(smallest, min(n, largest))

Now you can call it on your variables as

r = clamp(r, 0, 255)

Answer 2

You can use min and max.

r = min(max(r, 0), 255)

The inner expression makes sure r is at least 0. The outer expression makes sure it's no more than 255.

Answer 3

To answer your question on shorting the if statement code you provided and not providing an alternative solution to getting the same result as your if statement.

def rgb_8bit_trunc(r,g,b):
 print("Input: r:{}, g:{}, b:{}".format(r,g,b))
 r = 0 if r < 0 else r if r < 255 else 255
 g = 0 if g < 0 else g if g < 255 else 255
 b = 0 if b < 0 else b if b < 255 else 255
 print("Output: r:{}, g:{}, b:{}".format(r,g,b))
rgb_8bit_trunc(256,256,256)
rgb_8bit_trunc(-1,-1,-1)

Each ternary conditional operator is equivalent to the if statement code below where 'value' may be any of your RGB variables.

if value < 255:
 if value < 0:
 value = 0
 else:
 value
else:
 value = 255