filter()
filter() is a Python function in the Built-in Functions category. Filters elements from an iterable where the function returns True. The syntax is filter(function, iterable). Parameters: function — callable returning bool. Returns: Iterator. A typical example: list(filter(lambda x: x > 0, [-1, 0, 1, 2])) # [1, 2]. A close sibling is print(), which prints objects to the text stream, separated by `sep` and followed by `end`. A close sibling is len(), which returns the length (number of items) of an object. Works with sequences, collections, and strings. A close sibling is range(), which returns an immutable sequence of numbers. Commonly used in for loops. A close sibling is type(), which returns the type of an object, or creates a new type with three arguments. More about this category: Python's built-in functions available without importing — print, len, range, map, and more. For a broader walkthrough, read the Built-in Functions guide.