Function to trim/extend array, tuple,  bytes or string to a fixed number of elements:

def trimmed(arg, nr_of_elements, f=None):
    return (arg + arg.__class__([f, ] * nr_of_elements)
            if isinstance(arg, (tuple, list))
            else (arg + arg.__class__((f or " ") * nr_of_elements)
                  if isinstance(arg, (str, bytes))
                  else [arg, ] + [f, ] * nr_of_elements))[:nr_of_elements]

("f" is what is used to fill missed elements; should be compatible with 'arg')

trimmed([1,2,3], 5) # returns list: [1, 2, 3, None, None]

trimmed((1,2,3), 5) # returns tuple: (1, 2, 3, None, None)

trimmed([1, 2, 3, 4, 5, 6, 7, 8, 9], 5) # returns list: [1, 2, 3, 4, 5]

trimmed("Sample", 10, ".") # returns string: "Sample...."

trimmed(b'123', 5, b'.') # returns bytes: b'123..'

trimmed(10, 5, 1) # returns [10, 1, 1, 1, 1]

trimmed(10, 5, [1, 2, 3]) # returns [10, [1, 2, 3], [1, 2, 3], [1, 2, 3], [1, 2, 3]]

trimmed([], 5, 1) # returns list: [1, 1, 1, 1, 1]

trimmed((), 5, 1) # returns tuple: (1, 1, 1, 1, 1)

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