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A question was posted about chained comparison operators and how they are interpreted in different languages.
Chaining comparison operators means that (x < y < z) would be interpreted as ((x < y) && (y < z)) instead of as ((x < y) < z).
The comments on that question show that Python, Perl 6, and Mathematica support chaining comparison operators, but what other languages support this feature and why is it not more common?
A quick look at the Python documentation shows that this feature has been since at least 1996. Is there a reason more languages have not added this syntax?
A statically typed language would have problems with type conversion, but are there other reasons this is not more common?
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Python supports chaining of comparison operators, which means if we wanted to find out if b lies between a and c we can do a < b < c , making code super-intuitive. Python evaluates such expressions like how we do in mathematics.
Chaining with the comparison operator == returns True only if all values are equal. If there is even one different value, False is returned. Be careful when using the comparison operator !=
Equal to ( === ) — returns true if the value on the left is equal to the value on the right, otherwise it returns false .
Summary. A comparison operator compares two values and returns a boolean value, either True or False . Python has six comparison operators: less than ( < ), less than or equal to ( <= ), greater than ( > ), greater than or equal to ( >= ), equal to ( == ), and not equal to ( != ).
It should be more common, but I suspect it is not because it makes parsing languages more complex.
Benefits:
Drawbacks:
As to why not, my guesses are:
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The benefit is too small to justify complicating the language.
You don't need it that often, and it is easy to get the same effect cleanly with a few characters more.
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