3/28/2023 0 Comments Enumerate python![]() ![]() for index, value in enumerate(joint_values): Now, when this is useful? A possible use case is when you want to iterate over items, and you want to skip a specific item that you only know its index in the list but not its value (because its value is not known at the time). So if you have a list say l =, the list(enumerate(l)) will give you something like this. unpacking case and using a standard C integer value for the counter until the counter becomes too large to avoid using a Python integer object (which is unbounded).Īs other users have mentioned, enumerate is a generator that adds an incremental index next to each item of an iterable. The actual implementation in C is closer to the latter, with optimisations to reuse a single tuple object for the common for i. ![]() # return an iterator that adds a counter to each element of it If you were to re-implement enumerate() in Python, here are two ways of achieving that one using unt() to do the counting, the other manually counting in a generator function: from itertools import count > for count, elem in enumerate(elements):īy default, enumerate() starts counting at 0 but if you give it a second integer argument, it'll start from that number instead: > for count, elem in enumerate(elements, 42): So for each element in cursor, a tuple is produced with (counter, element) the for loop binds that to row_number and row, respectively.ĭemo: > elements = ('foo', 'bar', 'baz') The enumerate() function adds a counter to an iterable. ![]()
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