String Manipulation

1. Python- Strings
• Strings are amongst the most popular types in Python.
• We can create them simply by enclosing characters in quotes.
• Python treats single quotes the same as double quotes.
• Creating strings is as simple as assigning a value to a variable.
For example
var1 = 'Hello World!'
var2 = "Python Programming"
Accessing Values in Strings
• Python does not support a character type; these are treated as strings of length one, thus
also considered a substring.
• To access substrings, use the square brackets for slicing along with the index or indices to
obtain your substring.
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2. Python- Strings
• Example:
var1 = 'Hello World!'
var2 = "Python Programming"
print ("var1[0]: ", var1[0])
print ("var2[1:5]: ", var2[1:5])
• Updating Strings
You can "update" an existing string by (re)assigning a variable to another string.
The new value can be related to its previous value or to a completely different string
altogether.
For example-
#!/usr/bin/python3
var1 = 'Hello World!'
print ("Updated String :- ", var1[:6] + 'Python')
Output:
var1[0]: H
var2[1:5]: ytho
Output:
Updated String :- Hello Python
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3. Python- Strings
• Escape Characters
• Following table is a list of escape or non-printable characters that can be represented with
backslash notation.
• An escape character gets interpreted; in a single quoted as well as double quoted strings.
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4. Python- Strings
• String Special Operators
• Assume string variable a holds 'Hello' and variable b holds 'Python', then-
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5. Python- Strings
• String Special Operators
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6. Python- Strings
• String Formatting Operators
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7. Python- Strings
• String Formatting Operators
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8. Python- Strings
• Other supported symbols and functionality
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9. Python- Strings
• Unicode String
• In Python 3, all strings are represented in Unicode. In Python 2 are stored internally as 8-
bit ASCII, hence it is required to attach 'u' to make it Unicode. It is no longer necessary
now.
• Built-in String Methods
• Python includes the following built-in methods to manipulate strings-
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10. Python- Strings
• Unicode String
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11. Python- Strings
• Unicode String
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12. Python- Strings
• Unicode String
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13. Python- Strings
• Unicode String
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14. Python- Strings
• Unicode String
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15. Python- Strings
• Unicode String
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16. Python- Strings
• Unicode String
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17. Python- Strings
• Unicode String
String capitalize() Method
It returns a copy of the string with only its first character capitalized.
Syntax
str.capitalize()
Example:
str = "this is string example”
print ("str.capitalize() : ", str.capitalize())
Output:
str.capitalize() : This is string example
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18. Python- Strings
Output:
str.capitalize() : This is string example
str.center(40, 'a') : aaaathis is string
exampleaaaa
String center() Method
The method center() returns centered in a string of length width. Padding is done using
the specified fillchar. Default filler is a space.
Syntax
str.center(width[, fillchar])
Parameters
• width - This is the total width of the string.
• fillchar - This is the filler character.
Return Value
This method returns a string that is at least width characters wide, created by padding the
string with the character fillchar (default is a space).
Example
The following example shows the usage of the center() method.
#!/usr/bin/python3
str = "this is string example.
print ("str.center(40, 'a') : ", str.center(40, 'a'))
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