Strings


String function in python
Python capitalize() method converts first character of the string into uppercase without altering the whole string. It changes the first character only and skips rest of the string unchanged.
Signature
1.    capitalize()  
Parameters
No parameter is required.
Return Type
It returns a modified string.
# Python capitalize() function example  
# Variable declaration  
str = "welcome"  
# Calling function  
str2 = str.capitalize()  
# Displaying result  
print("Old value:", str)  
print("New value:", str2) 

output:

Old value: welcome
New value: Welcome


Python String Casefold() Method

Python Casefold() method returns a lowercase copy of the string. It is more simillar to lowercase method except it revomes all case distinctions present in the string.
For example in German, 'β' is equivelent to "ss". Since it is already in lowercase, lowercase do nothing and prints 'β' whereas casefold converts it to "ss".

Signature
casefold()  
Python String Casefold() Method Example 1
# Python casefold() function example  
# Variable declaration  
str = "WELCOME"  
# Calling function  
str2 = str.casefold()  
# Displaying result  
print("Old value:", str)  
print("New value:", str2)  
Output:
Old value: WELCOME
New value: welcome

Python String Center() Method

Python center() method alligns string to the center by filling paddings left and right of the string. This method takes two parameters, first is a width and second is a fillchar which is optional. The fillchar is a character which is used to fill left and right padding of the string.

Signature

1.    center(width[,fillchar])  

Parameters

  • width (required)
  • fillchar (optional)
# Python center() function example  
# Variable declaration  
str = "Welcome to world"  
# Calling function  
str2 = str.center(20)  
# Displaying result  
print("Old value:", str)  
print("New value:", str2)  
Output:
Old value: Welcome to world
New value:   Welcome to world

Python String Center() Method Example 2
Here, we are providing padding char (optional) parameter as #. See the example.
# Python center() function example  
# Variable declaration  
str = "Welcome"  
# Calling function  
str2 = str.center(20,'#')  
# Displaying result  
print("Old value:", str)  
print("New value:", str2)  
Output:
Old value: Welcome
New value: ##Welcome##

Python String Count() Method

It returns the number of occurences of substring in the specified range. It takes three parameters, first is a substring, second a start index and third is last index of the range. Start and end both are optional whereas substring is required.

Signature

1.    count(sub[, start[, end]])  

Parameters

  • sub (required)
  • start (optional)
  • end (optional)
# Python count() function example  
# Variable declaration  
str = "Welcome"  
str2 = str.count('e')  
# Displaying result  
print("occurences:", str2)  
Output:
occurences: 2

Python String endswith() Method

Python endswith() method returns true of the string ends with the specified substring, otherwise returns false.

Signature

1.    endswith(suffix[, start[, end]])  

Parameters

  • suffix : a substring
  • start : start index of a range
  • end : last index of the range
Start and end both parameters are optional.

Return Type

It returns a boolean value either True or False.
# Python endswith() function example  
# Variable declaration  
str = "Hello this is javatpoint."  
isends = str.endswith(".")  
# Displaying result  
print(isends) 

Output:
True

Python String isalnum() Method

Python isalnum() method checks whether the all characters of the string is alphanumeric or not. A character which is either a letter or a number is known as alphanumeric. It does not allow special chars even spaces.

Signature

isalnum()  

Parameters

No parameter is required.

# Python isalnum() function example  
# Variable declaration  
str = "Welcome"  
# Calling function  
str2 = str.isalnum()  
# Displaying result  
print(str2)  
Output:
True

Python String isspace() Method

Python isspace() method is used to check space in the string. It returna true if there are only whitespace characters in the string. Otherwise it returns false. Space, newline, and tabs etc are known as whitespace characters and are defined in the Unicode character database as Other or Separator.

Signature

1.    isspace()  

Parameters

No parameter is required.

Return

It returns either True or False.
# Python isspace() method example  
# Variable declaration  
str = " " # empty string  
# Calling function  
str2 = str.isspace()  
# Displaying result  
print(str2)  

Output:
True

Python String isspace() Method Example 3
isspace() method returns true for all whitespaces like:
  • ' ' - Space
  • '\t' - Horizontal tab
  • '\n' - Newline
  • '\v' - Vertical tab
  • '\f' - Feed
  • '\r' - Carriage return
# Python isspace() method example  
# Variable declaration  
str = " " # string contains space  
if str.isspace() == True:  
    print("It contains space")  
else:  
    print("Not space")  
str = "ab cd ef \n"  
if str.isspace() == True:  
    print("It contains space")  
else:  
    print("Not space")  
str = "\t \r \n"  
if str.isspace() == True:  
    print("It contains space")  
else:  
    print("Not space")  
Output:
It contains space
Not space
It contains space


Python String join() Method

Python join() method is used to concat a string with iterable object. It returns a new string which is the concatenation of the strings in iterable. It throws an exception TypeError if iterable contains any non-string value.
It allows various iterables like: List, Tuple, String etc.

Signature

join(iterable)  

Parameters

iterable : iterable object like: List, Tuple, String etc.
# Python join() method example  
# Variable declaration  
str = ":"   # string  
list = ['1','2','3']    # iterable  
# Calling function  
str2 = str.join(list)  
# Displaying result  
print(str2)  
Output:
1:2:3

Python String lstrip() Method

Python lstrip() method is used to remove all leading characters from the string. It takes a char type parameter which is optional. If parameter is not provided, it removes all the leading spaces from the string.

Signature

1.    lstrip([chars])  

Parameters

chars (optional) : A list of chars

Return

It returns a string.
Let's see some examples of lstrip() method to understand it's functionality

Python String lstrip() Method Example 1

A simple program to understand use of lstrip method. See how it removes leading spaces.
# Python lstrip() method example  
# Variable declaration  
str =  "  Hello  "  
# Calling function  
str2 = str.lstrip()  
# Displaying result  
print(str)  
print(str2)  
Output:
        Hello  
Hello

Python String partition() Method

Python partition() method splits the string from the string specified in parameter. It splits the string from at the first occurrence of parameter and returns a tuple. The tuple contains the three parts before the separator, the separator itself, and the part after the separator.
It returns an empty tuple having seperator only, if the seperator not found.
The method signature is given below.

Signature

1.    partition(sep)  

Parameters

sep: A string parameter which separates the string.

Return

It returns a tuple, A 3-Tuple.
Let's see some examples of partition(sep) method to understand it's functionality.

Python String partition() Method Example 1

First, let's see simple use of partition method.
# Python partition() method example  
# Variable declaration  
str = "Java is a programming language"  
# Calling function  
str2 = str.partition("is")  
# Displaying result  
print(str2)  
# when seperate from the start  
str2 = str.partition("Java")  
print(str2)  
# when seperate is the end  
str2 = str.partition("language")  
print(str2)  
# when seperater is a substring  
str2 = str.partition("av")  
print(str2)  

Python String partition() Method Example 2

if the separator is not found, It returns a tuple containing string itself and two empty strings. See the example below.
# Python partition() method example  
# Variable declaration  
str = "Java is a programming language"  
# Calling function  
str2 = str.partition("not")  
# Displaying result  
print(str2)  
Output:
('Java is a programming language', '', '')

Python String replace() Method

Return a copy of the string with all occurrences of substring old replaced by new. If the optional argument count is given, only the first count occurrences are replaced.

Signature

replace(old, new[, count])  

Parameters

old : An old string which will be replaced.
new : New string which will replace the old string.
# Python replace() method example  
# Variable declaration  
str = "Java is a programming language"  
# Calling function  
str2 = str.replace("Java","C")  
# Displaying result  
print("Old String: \n",str)  
print("New String: \n",str2)  
Output:
Old String:
 Java is a programming language
New String:
 C is a programming language


Python String rstrip() Method

Python rstrip() method removes all the trailing characters from the string. It means it removes all the specified characters from right side of the string. If we don't specify the parameter, It removes all the whitespaces from the string. This method returns a string value.

Signature

rstrip([chars])  

Parameters

chars: character to be removed from the string.

Return

It returns string.
    # Python rstrip() method example  
# Variable declaration  
str = "Java and C# "  
# Calling function  
str2 = str.rstrip()  
# Displaying result  
print("Old string: ",str)  
print("New String: ",str2)  
Output:
Old string:  Java and C#
New String:  Java and C#

Python String swapcase() Method

Python swapcase() method converts case of the string characters from uppercase to lowercase and vice versa. It does not require any parameter and returns a string after case conversion.

Signature

1.    swapcase()  

Parameters

No Parameter

Return

It returns a string.
Let's see some examples of swapcase() method to understand it's functionality.

Python String swapcase() Method Example 1

It is a simple example to convert uppercase to lowercase using the swapcase() method.
# Python String swapcase() method  
# Declaring variable  
str = "WELCOME"  
# Calling function  
str2 = str.swapcase()  
# Displaying result  
print (str2)  
Output:
Welcome
 
 
 

Python String zfill() Method

Python zfill() method fills the string at left with 0 digit to make a string of length width. It returns a string contains a sign prefix + or - before the 0 digit.
It returns original length string if the width is less than string length.
Signature
zfill(width)  
 


# Python zfill(width) method   
# Declaring variables  
text = "Zfill Example"  
# Calling Function  
str2 = text.zfill(20)  
# Displaying result  
print(str2)  
Output:
0000000Zfill Example





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