Python slice()

 text = 'Python Programing' 
# get slice object to slice Python sliced_text = slice(6)
 print(text[sliced_text]) # Output: Python

slice() Syntax

The syntax of slice() is:

slice(start, stop, step)

slice() Parameters

slice() can take three parameters:

• start (optional) - Starting integer where the slicing of the object starts. Default to None if not provided.
• stop - Integer until which the slicing takes place. The slicing stops at index stop -1 (last element).
• step (optional) - Integer value which determines the increment between each index for slicing. Defaults to None if not provided.

slice() Return Value

slice() returns a slice object.

Note: We can use slice with any object which supports sequence protocol (implements __getitem__() and __len()__ method).

Example 1: Create a slice object for slicing

 # contains indices (0, 1, 2) result1 = slice(3) print(result1) # contains indices (1, 3) 
result2 = slice(1, 5, 2)
 print(slice(1, 5, 2))

Output

 slice(None, 3, None) slice(1, 5, 2)

Here, result1 and result2 are slice objects.

Now we know about slice objects, let's see how we can get substring, sub-list, sub-tuple, etc. from slice objects.

Example 2: Get substring using slice object

 # Program to get a substring from the given string py_string = 'Python' # stop = 3 # contains 0, 1 and 2 indices 
slice_object = slice(3) 
 print(py_string[slice_object]) # Pyt # start = 1, stop = 6, step = 2 # contains 1, 3 and 5 indices slice_object = slice(1, 6, 2) print(py_string[slice_object]) # yhn

Output

 Pyt yhn

Example 3: Get substring using negative index

 py_string = 'Python' # start = -1, stop = -4, step = -1 # contains indices -1, -2 and -3 
slice_object = slice(-1, -4, -1)
 print(py_string[slice_object]) # noh

Output

 noh

Example 4: Get sublist and sub-tuple

 py_list = ['P', 'y', 't', 'h', 'o', 'n'] py_tuple = ('P', 'y', 't', 'h', 'o', 'n') # contains indices 0, 1 and 2 
slice_object = slice(3)
 print(py_list[slice_object]) # ['P', 'y', 't'] # contains indices 1 and 3 
slice_object = slice(1, 5, 2)
 print(py_tuple[slice_object]) # ('y', 'h') 

Output

 ['P', 'y', 't'] ('y', 'h')

Example 5: Get sublist and sub-tuple using negative index

 py_list = ['P', 'y', 't', 'h', 'o', 'n'] py_tuple = ('P', 'y', 't', 'h', 'o', 'n') # contains indices -1, -2 and -3 
slice_object = slice(-1, -4, -1) 
 print(py_list[slice_object]) # ['n', 'o', 'h'] # contains indices -1 and -3 
slice_object = slice(-1, -5, -2)
 print(py_tuple[slice_object]) # ('n', 'h')

Output

 ['n', 'o', 'h'] ('n', 'h')

Example 6: Using Indexing Syntax for Slicing

The slice object can be substituted with the indexing syntax in Python.

You can alternately use the following syntax for slicing:

obj[start:stop:step]

For example,

 py_string = 'Python' # contains indices 0, 1 and 2 
print(py_string[0:3]) # Pyt
 # contains indices 1 and 3 
print(py_string[1:5:2]) # yh

Output

 Pyt yh

Also Read:

• Python Program to Slice Lists
• Pandas slice()