slice() to get slice object to use in breaking of list, tuple, string and other iterable objects

slice(start,stop,step) returns slice object for breaking string, list , tuple etc.

start	(optional) default = 0 , The start position of the slice
stop	( required ), slice should Stop before this position
step	( optional ) default =1 , step to consider for slicing

slice() with start stop and step positions

Start, stop and step values are indices of a range.

If one value is given then it is considered as stop value as default start is 0 and step value is 1.
If two values are given then it is considered as start and stop values and step value is set to 1
If three values are given then they are considered as start , stop and step values.

creating slice object

obj_slice1=slice(2) 
print(obj_slice1)       # slice(None, 2, None)
obj_slice2=slice(2,4)   
print(obj_slice2)       # slice(2, 4, None)
obj_slice3=slice(2,4,2)
print(obj_slice3)       # slice(2, 4, 2)

applying slice object

We will apply these slice objects to our list, tuple, string etc to break them at different positions.

Let us use slice object to break a list. While creating the slice object we have taken one parameter only so it will be used as stop value. Here start = 0 , stop=2 and step =1. Starting from 0^th position, the slice will stop before 2 ( i.e at the 1^st position ). The default value for step is 1.

obj_slice=slice(2)
my_list=[5,2,1,4,9,3,6]
print(my_list[obj_slice])  # [5,2]

Now start=2, stop=5 and step=1

obj_slice=slice(2,5,1)
my_set=(5,2,1,4,9,3,6)
print(my_set[obj_slice]) # (1,4,9)

Using a string

start=2, stop=5, step=1

obj_slice=slice(2,5)
my_str='plus2net'
print(my_str[obj_slice]) # us2

Using negative indices

Count position from right end.

obj_slice=slice(-5,-2)
my_str='plus2net'
print(my_str[obj_slice]) # s2n

obj_slice=slice(-7,-1,2)
my_str='plus2net'
print(my_str[obj_slice]) # lsn

data type of slice()

We will use type() to get the data type of the slice object

obj_slice=slice(1,5,1)
print(type(obj_slice)) # <class 'slice'>

Why we can apply slice object to a set ?

obj_slice=slice(2,5)
my_set={5,2,1,4,9,3,6}
print(my_set[obj_slice])

Error will be generated.

TypeError: 'set' object is not subscriptable

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Subhendu Mohapatra

Author & Instructor at plus2net

I write and maintain practical tutorials on Python, PHP, SQL, JavaScript, HTML, jQuery, and web development at plus2net. The tutorials focus on clear explanations, working examples, and code that readers can test and adapt while learning.

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