Python Strings

1. Datatypes
2. String

The string is simply the combination of characters. In Python, strings are quoted by either single quotation or double quotation. For example, "PythonTheRightWay" or 'PythonTheRightWay' both are strings.

Strings can be created by writing the value of the string inside the quotation mark

name="PythonTheRightWay" #assigning the string value to name
print(name) #printing the string

PythonTheRightWay

The string values can also be enclosed within the single triple quotation or in double quotation marks in order to represent a multiline statement or docstring respectively.

    
def string():
    '''This is the docstring part
        inside triple quotation part''' #python docstring.
    pass

print(string.__doc__()) #printing the docstring

a=""" Python is high-level programming languages
    which syntax is extremely very simple and is
    like the English language """ #multiline statement
print(a) 

This is the docstring part inside triple quotation part
Python is high-level programming languages
which syntax is extremely very simple and is
like the English language

Strings are the combination of character Unicode. Strings are also an array of characters. All the characters are indexed in the string and these can be accessed and modified with the help of the string index

name="Python"
print(name[0]) #printing the 0 index character from string
print(name[1]) #printing the 1 index character from string
print(name[2]) #printing the 2 index character from string
print(name)

P
y
t

You can return a range of characters by using the slice syntax. Specify the start index and the end index, separated by a colon, to return a part of the string.

name="PythonTheRightWay"
>>>print(name[4:]) #slicing from 4th to last character
   onTheRightWay

>>>print(name[:6]) #slicing from 6th to first character
   Python

>>>print(name[6:13]) #slicing from 6th to 13th character
   TheRight

>>>print(name[-1]) #last character
   y

>>>print(name[0])
   p

Strings are immutable. This means that elements of a string cannot be changed once they have been assigned. We can simply reassign different strings to the same name

>>> my_name='PythonTheRightWay'
>>> my_name[4] = 'i'
    ...
    TypeError: 'str' object does not support item assignment
>>> my_name = 'Python' #completely reassign
>>> my_name
    'Python'

Since strings are arrays, we can loop through the characters in a string, with a for loop

string="Python"
for char in string:
    print(char,end= " ") #deault end is a "\n" (new line)
                         # but we override it to a space

P y t h o n

Combining two or more strings to make a single string is called string concatenation. We can concatenate 2 or more strings by using operators '+' and '*'

str1="python"
str2="rightway"

concat1=str1+str2 #using "+" operator
concat2=str1*3 #using "*" operator

print(concat1)
print(concat2)

pythontherightway
pythonpythonpython

We can test if a substring exists within a string or not, using the keyword in

>>>'a' in 'python'
    False
>>>'ontheright' in 'pythontherightway'
    True

There are various methods available with the string object. Some of them are:

• lower()
• upper()
• join()
• split()
• find()
• replace()

>>>"PythonTheRightWay".upper()
    PYTHONTHERIGHTWAY

>>>"PythonTheRightWay".lower()
    pythontherightway

>>>"This will split all words into a list".split()
    ['This', 'will', 'split', 'all', 'words', 'into', 'a', 'list']'

>>> ' '.join(['This', 'will', 'join', 'all', 'words', 'into', 'a', 'string'])
    'This will join all words into a string'

>>>'Happy New Year'.find('ew')
    7

>>>'Happy New Year'.replace('Happy','Brilliant')
    'Brilliant New Year'

name = "PythonTheRightWay"
print(name[::-1])

yaWthgiRehTnohtyP