CODEWITHSUNDEEP
pythonif-statement
Gao
Gao

Reputation: 103

Simplification of if multiple conditions in python

I want to pick out some items in one rectangular box with axis limits of (xmin, xmax, ymin, ymax, zmin, zmax). So i use the following conditions, 

if not ((xi >= xmin and xi <= xmax) and (yi >= ymin and yi <= ymax) and (zi >= zmin and zi <= zmax)):
    expression

But I think python has some concise way to express it. Does anyone can tell me?

Upvotes: 6

Views: 192

Answers (2)

AltShift
AltShift

Reputation: 346

If you really want to start cooking with gas, create a class library for handling 3D points (e.g. by extending this one to include the Z coordinate: Making a Point Class in Python).

You could then encapsulate the above solution into a method of the class, as:

def isInBox(self, p1, p2):
    return (p1.X <= self.X <= p2.X and p1.Y <= self.Y <= p2.Y and p1.Z <= self.Z <= p2.Z)

Upvotes: 1

Jean-Fran&#231;ois Fabre
Jean-Fran&#231;ois Fabre

Reputation: 140148

Typical case for operator chaining:

if not (xmin <= xi <= xmax and ymin <= yi <= ymax and zmin <= zi <= zmax):

Not only it simplifies the comparisons, allowing to remove parentheses, while retaining readability, but also the center argument is only evaluated once , which is particularly interesting when comparing against the result of a function:

if xmin <= func(z) <= xmax:

(so it's not equivalent to 2 comparisons if func has a side effect)

Upvotes: 14

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