python string operations

• In python, we have some operations that perform the specified operations on strings.
• In this, the string must enclose with the codes that might be single or double.
• Here are some python string operations.

1.  String assignment operator:

• In this operator, the string is assigned to any of the variables.
• The string may be in single or double codes.
• It is represented by " =" equal to symbol.

Syntax: string ="any variable."

Example:  string1="python"

                  string2="java"

In the above example, we assign a "python" to string 1 and "java" to string 2 by using the" =" symbol.

# write a python program for the string assignment operator.

1. str1="welcome to python"
2. str2="Today topic is string operator"
3. str3="python is easy  language"
4. print(str1)
5. print(str2)
6. print(str3)

output:  welcome to python

             Today topic is string operator

             Python is easy to language

2. Cancatenate operator:

• This operator has used to cancate the strings.
• Concatenation means joining or combing the strings by using the plus symbol between the strings.
• It is represented by the symbol " +".

       Syntax:  (str1+str2)

       Example:   "Hello"  +"world"

•  Result is : "Helloworld"

#Write a python program using string cancatenate operator.

1. str1="a"
2. str2="is"
3. str3="alphabet"
4. print(str1+str2+str3)

output: aisaphabet

3. String repetition operator: 

• In this operator, the string is repeated the number of times that we declare in the code.
• It is represented by the symbol "*".

Syntax:  str*n    Here n is the number of times that the string can be repeated.

Example: str="apple"

                 str*2

The result is: apple apple

• here we declare the string as apple it should be repeated for 2 times.

#Write a python code using the string repetition operator.

1. str="welcome"
2. print(str*5)

output: welcome welcome welcome

       

       4.Slicing operator:  

• In this slicing operator, the strig is divided according to the given index values.
• The string can y accessed by using the index.
•  It is having positive index and negative index values.
• Positive values start from  0 from left to right.
• The negative index starts from -1 from right to left.
• [:] this gives all values in the index 0 to end. 
• The slicing never shows the error, if the index is out of range, it shows an empty list[].  

Syntax: str[]

Example:   str="string"

                   str[0]=s

                   str[1]=t

                   str[-1]=g

• In the above example, the s index is 0 so it returns s when we write str[0].

#write a python code for slicing operator.

1. str="coding"
2. print(str[0])
3. print(str[-1])
4. print(str[1:6])
5. print(str[1:])
6. print(str[:3])
7. print(str[1:-4])
8. print(str[-3])

output:  c

             g

             oding

             oding

             cod

              o

              i                                                                                 

                                       

5. String comparison operator:

• In the string comparison operator, we compare the strings.
• In this, we have 2 operator

     1.Equal to(==): If both the strings are the same then it returns true else false.

• It is represented by the symbol "==".

     Syntax:str1==str2.

       2.not equal(!=): If both strings are not the same then it true else false.

• It is represented by the symbol "!=".

Syntax:  str1!=str2

#write a python coding using the python string comparison operator.

1. str1="my name is A"
2. str2="my name is B"
3. str3="my name is A"
4. str4="apple"
5. str5="apple"
6. print(str1==str2)
7. print(str1==str1)
8. print(str4==str5)
9. print(str4!=str1)
10. print(str3!=str2)

output: false

            true

            true

            true

            true

6. Membership operator:

• In the membership operator, we check the string that is declared in the code is present in the given list or not.
• There are 2 operators in membership.

1. In:  It tells that the string is present in the given list.If it is present returns true else false.
2. Not in: It tells that the string is not present in the given list returns true else false.

Example: str="string"

                r in the str

       The result is: true

#write python code using membership operator.

1. str="Hello world"
2. print("H" in str)
3. print('s' in str)
4. print("a" not in str)

output:  true

             false

             true

7. Escape sequence operator:

• This operator is used when an unallowed character is present in the given string.
• It is represented by the "\" symbol called backslash. 

Write a python program for escape sequence operator.

1. str="welcome to \"python\" classes"
2. print(string)

output: welcome to "python" classes

8.String formatting operator:

• It is used to format the string as per our requirement.
• There are different types of formats.
• It is denoted by that "%" symbol.
• Each format has its own meaning.

%d:  used for sign decimal integer.

%s: used for string.

%f: used for floating.

%u: used for unsigned decimal integer.

%c: used for the character.

#write a python code using the string formatting operator.

1. name="abc"
2. marks=78
3. str1='hi % s'%(name)
4. print(str1)
5. str2='hi% s,my marks is %f'%(name,marks)
6. print(str2)

output: hiabc,my marks is 78.000000