How to find range overlap in python?

python range
drbunsen picture drbunsen · Jul 25, 2011 · Viewed 52.1k times · Source

What is the best way in Python to determine what values in two ranges overlap?

For example:

x = range(1,10)
y = range(8,20)

(The answer I am looking for would be the integers 8 and 9.)

Given a range, x, what is the best way to iterate through another range, y and output all values that are shared by both ranges? Thanks in advance for the help.

EDIT:

As a follow-up, I realized that I also need to know if x does or does not overlap y. I am looking for a way to iterate through a list of ranges and and do a number of additional things with range that overlap. Is there a simple True/False statement to accomplish this?

Answer

Andrew Clark picture Andrew Clark · Jul 25, 2011

If the step is always +1 (which is the default for range) the following should be more efficient than converting each list to a set or iterating over either list:

range(max(x[0], y[0]), min(x[-1], y[-1])+1)

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