Introduction

Python is a high-level, general-purpose programming language widely utilized for developing GUI applications and web applications. Slicing in Python, it is highly advantageous in rapid application development due to its dynamic typing and binding capabilities. This article will explore a fundamental topic: Slicing in Python.

What Is an Index?

An index is a numerical value denoting the position of a character or element within a list, tuple, or string. The index is typically assigned in ascending order, beginning with 0 and ending with one less than the total number of items. Negative indexes can be employed to access elements from the end of a container, rather than from the start. 

What Is Slicing?

Slicing in Python utilizes the slice function, allowing programmers to extract data from strings. This article outlines multiple approaches for achieving this effect. Slicing is not limited to strings, but can also be applied to tuples and lists. It involves the extraction of a part of a string, list, or tuple by specifying the indices of the desired range of elements.

Syntax: Object [start:stop: step]

The “start” parameter denotes the initial index of a slice.

“Stop” sets the ending element of a slice

You may selectively omit items by utilizing one of these.

Note: The search shall commence at index one (inclusive) and conclude at index six (exclusive).

Slice() Function in Python

The slice() method extracts a section of data and returns it as a new, unmodified sequence. This allows users to extract specific elements from the data without altering them. Click here to know about data science course in Kolkata

Syntax: slice(start,stop,step)

Python slice string

# String slicing

String = ‘DataTrained’

s1 = slice(3)

s2 = slice(1, 5, 2)

print(“String slicing”)

print(String[s1])

print(String[s2])

Python Slice list or Python Slice Array

# List slicing

L = [1, 2, 3, 4, 5]

s1 = slice(3)

s2 = slice(1, 5, 2)

print(“List slicing”)

print(L[s1])

print(L[s2])

Python slice tuple

# Tuple slicing

T = (1, 2, 3, 4, 5)

s1 = slice(3)

s2 = slice(1, 5, 2)

print(“Tuple slicing”)

print(T[s1])

print(T[s2])

Negative Indexing

In Python, negative sequence indexes indicate positions from the end of an array. The slice() function can also have negative values; in this case, the iteration will be done in reverse, starting from the end and going to the beginning. To know more about data analyst course in Delhi

# list -ve index slicing

l = [‘a’, ‘b’, ‘c’, ‘d’, ‘e’]

slice_obj = slice(-2, -6, -1)

print(“list slicing:”, l[slice_obj])

# string -ve index slicing

s = “geeks”

slice_obj = slice(-1)

print(“string slicing:”, s[slice_obj])

# tuple -ve index slicing

t = (1, 3, 5, 7, 9)

slice_obj = slice(-1, -3, -1)

print(“tuple slicing:”, t[slice_obj])

What Is Slicing in Python?

Slices are objects of the Python built-in class ‘slice’. Slicing in Python, They can be created using the statement ‘slice(start, stop, step)’. It is also possible to pass an instance of a slice in place of start:stop:

step or start:stop:

>>> s = slice(1, 5, 2)

>>> s

slice(1, 5, 2)

>>> s.start, s.stop, s.step

(1, 5, 2)

>>> tuple_[s]

(2, 8)

You can omit the step and still receive the same behavior as if you had used start:stop:

>>> s = slice(1, 5)

>>> s.start, s.stop, s.step

(1, 5, None)

>>> tuple_[s]

(2, 4, 8, 16)

If you pass in one argument, the slice will use it as the stop and act like a stop:

>>> s = slice(5)

>>> s.start, s.stop, s.step

(None, 5, None)

>>> tuple_[s]

(1, 2, 4, 8, 16)

Conclusion

This article demonstrates how Slicing in Python works. It is a powerful and valuable technique when extracting items from sequences such as strings, tuples, and lists, as well as third-party objects like NumPy arrays, slicing in Python arrays, Pandas series, and data frames.

Additionally, slices can be used within functions and methods. To enable access, modification, or deletion of data using the instance[index_or_slice] notation in classes, one should implement the special methods __getitem__(), __setitem__(), or __delitem__() and potentially apply Python slices.

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