Comprehensions Archives

December 28, 2020

You can, but should you? Combining some of Python’s more esoteric features

Note: As usual, readers of my blog (and my students) found a simpler and more elegant solution than I did… I knew that the boolean “or” operator returned the first “True” value it encountered, but I completely forgot that if it only encounters “False” values, it returns the final one. So there was a far…
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August 30, 2016

Implementing “zip” with list comprehensions

I love Python’s “zip” function. I’m not sure just what it is about zip that I enjoy, but I have often found it to be quite useful. Before I describe what “zip” does, let me first show you an example: >>> s = ‘abc’ >>> t = (10, 20, 30) >>> zip(s,t) [(‘a’, 10), (‘b’,…
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July 23, 2015

Understanding nested list comprehensions in Python

Bottom line: A nested list comprehension is just multiple “for” clauses in a single comprehension, read left to right, outermost first: [(x,y) for x in range(5) for y in range(5)]. Each additional “for” flattens the data by one more level, and every variable it defines is available to the output expression and to an optional…
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July 16, 2015

Want to understand Python’s comprehensions? Think in Excel or SQL.

Comprehensions are among the most useful constructs in Python. They merge the old, trusty “map” and “filter” functions into a single piece of compact, elegant syntax, allowing us to expression complex ideas in a minimum of code. Comprehensions are one of the most important tools in a Pythonista’s toolbox. And yet, I have found that…
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Tag: Comprehensions

You can, but should you? Combining some of Python’s more esoteric features

Implementing “zip” with list comprehensions

Understanding nested list comprehensions in Python

Want to understand Python’s comprehensions? Think in Excel or SQL.