extended slicing in python

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In Python, extended slicing is a way to slice a sequence with a specified step size, and to specify a different step size for the slicing of each dimension of a multidimensional sequence.

Here is an example of extended slicing in Python:

# Extended slicing of a list
my_list = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

# Extract every other element of the list, starting with the first element
extended_sliced_list = my_list[::2]
print(extended_sliced_list)  # Output: [0, 2, 4, 6, 8]

# Extract every other element of the list, starting with the second element
extended_sliced_list = my_list[1::2]
print(extended_sliced_list)  # Output: [1, 3, 5, 7, 9]

# Extended slicing of a multidimensional list
my_2d_list = [[0, 1, 2], [3, 4, 5], [6, 7, 8]]

# Extract the first and last elements of each sublist
extended_sliced_2d_list = my_2d_list[::2, ::2]
print(extended_sliced_2d_list)  # Output: [[0, 2], [6, 8]]

# Extract every other element of each sublist
extended_sliced_2d_list = my_2d_list[:, ::2]
print(extended_sliced_2d_list)  # Output: [[0, 2], [3, 5], [6, 8]]

In the first example, we use extended slicing to extract every other element of the list, starting with the first element (my_list[::2]) and starting with the second element (my_list[1::2]).

In the second example, we use extended slicing to extract elements from a multidimensional list. The syntax for extended slicing of a multidimensional list is [dim1_slice, dim2_slice, ...], where each dim_slice is a slice of the corresponding dimension. In the first slicing operation (my_2d_list[::2, ::2]), we extract the first and last elements of each sublist by slicing the first dimension with a step size of 2, and the second dimension with a step size of 2. In the second slicing operation (my_2d_list[:, ::2]), we extract every other element of each sublist by slicing the second dimension with a step size of 2.

Extended slicing can be a powerful tool for working with multidimensional sequences in Python. It allows us to extract and manipulate specific elements of a sequence with a high level of control and flexibility.

What is the default value of step for extended string slicing in python

The default value of the step parameter for extended slicing in Python is 1. This means that if you do not specify a value for the step parameter, it will be assumed to be 1.

Here is an example of extended slicing with the default step value of 1:

# Extended slicing with default step value of 1
my_string = "abcdefghij"

# Extract every character of the string
extended_sliced_string = my_string[::]
print(extended_sliced_string)  # Output: "abcdefghij"

# Extract every character of the string (same as my_string[::1])
extended_sliced_string = my_string[::1]
print(extended_sliced_string)  # Output: "abcdefghij"

In the above code In both of these examples, the step size is not specified, so the default value of 1 is used. This results in every character of the string being extracted.

Slice the string with steps of 2

You can also specify a step size other than 1 when performing extended slicing. For example:

# Extended slicing with a step size of 2
my_string = "abcdefghij"
extended_sliced_string = my_string[::2]
print(extended_sliced_string)  # Output: "acegi"

# Extended slicing with a step size of 3
my_string = "abcdefghij"
extended_sliced_string = my_string[::3]
print(extended_sliced_string)  # Output: "adgj"

In the above example code the step size is specified as 2 and 3, respectively, resulting in every other character and every third character being extracted.

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