I will be showing more examples of indexing and slicing as a form of my practice to familiarize this. From the previous lesson/posts, the syntax for slicing as follows:
string[start : end : step]
Example1: (Indexing and Slicing in Strings)
| W | r | i | t | e | C | o | d | e | O | n | l | i | n | e |
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 |
| -15 | -14 | -13 | -12 | -11 | -10 | -9 | -8 | -7 | -6 | -5 | -4 | -3 | -2 | -1 |
-print the word “Online”
>> str=’WriteCodeOnline’
>>> print(str)
WriteCodeOnline
>>> print(str[9:])
Online
-print the word “Onli”
>> print(str[9:13])
Onli
>>>
-print the word “teCo”
>>> print(str[3:7])
teCo
-print the word “Online” using the negative indexing
print(str[-6:])
Online
-print the word “Onli” using negative indexing
>>> print(str[-6:-2])
Onli
-print the word “teCo” using negative indexing
>> print(str[-12:-8])
teCo
Example2: (Indexing and Slicing in Lists)
| Write | Code | Online |
| 0 | 1 | 2 |
| -3 | -2 | -1 |
Indexing:
strlist = [‘Write’, ‘Code’, ‘Online’]
>>> print(strlist)
[‘Write’, ‘Code’, ‘Online’]
>>> print(strlist[0])
Write
>>> print(strlist[2])
Online
>>> print(strlist[-2])
Code
>> print(strlist[-2:-1])
[‘Code’]
Example3: Steps(Stride)
The “step” parameter is optional and the default is 1. It can be either positive or negative.
As mentioned about, just want to repeat again
string[start : end : step]
start-position end-position increment
e.g.
WRITECODE
Let say we want to specify the step of slicing by 2
[start:stop:2]
>> str = ‘WRITECODE’
>>> print(str)
WRITECODE
>>> print(str[::])
WRITECODE
>>> print(str[::1])
WRITECODE
>>> print(str[::2])
WIEOE
Let take this example:
>> print(str[1:8:3])
RED
str[1:8:3] = W R I T E C O D E
0 1 2 3 4 5 6 7 8
-starts from R and ends on D, as (E will not include)
-steps will start counting from R, take R, then count 0,1,2,3 then take that character, from E count again 0,1,2,3 and take that character
More example
-Display letter “t” in one line for word “Writecode”
>> ‘Writecode'[3:4]
‘t’
More indexing and slicing on next post