String Manipulation

String Manipulation

1. Traversing a String

   • Definition
     • Traversing a string in Python involves accessing each character within the string, one after the other
   • Techniques
     • for loop
     • while loop

2. String Operators

   • Concatenation
     • +
       • Eg. 'tea' + 'pot'
         • 'teapot'
   • Replication
     • *
       • Eg. 'go' * 3
         • 'gogogo'
   • Membership operators
     • in
       • The in operator in Python is a membership operator that checks if a value exists within a sequence, such as a list, tuple, string, or dictionary
         • Eg. 'a' in 'heya'
           • Returns True
     • not in
       • The not in operator in Python checks if a value is not present in a sequence (like a list, tuple, string, or set). It returns True if the value is not found and False if it is found.
         • Eg. 'a' not in 'heya'
           • Returns False
   • Comparison Operator
     • Compares two strings on the basis of ASCII values of the characters using <, >, <=, >=, ==, !=
       • Example
         • "a" == "a"

3. String Slicing

   • Definition
     • String slicing in Python extracts a substring from a string. It uses the syntax string[start:stop:step]
   • Example
     • s[1:7:2]

4. Built-in functions

   • split()
     • The split() method splits a string into a list.
   • len()
     • The len() function determine the number of items in an object
   • capitalize()
     • The capitalize() function that converts the first character of a string to uppercase and the rest of the characters to lowercase
   • title()
     • The title() converts the first character of each word in a string to uppercase and the remaining characters to lowercase.
   • lower()
     • The lower() function that converts all uppercase characters in a string to lowercase
   • upper()
     • The upper() function that converts all lowercase characters in a string to uppercase
   • count()
     • The count() method returns the number of times a specified value appears in the string
   • find()
     • The find() method finds the first occurrence of the specified value. The find() method returns -1 if the value is not found.
   • index()
     • The index() method finds the first occurrence of the specified value. The index() method raises an exception if the value is not found
   • endswith()
     • The endswith() method in Python is used to check if a string ends with a specified suffix. It returns True if the string ends with the suffix, and False otherwise. The suffix can be a string or a tuple of strings.
   • startswith()
     • The startswith() used to check if a string begins with a specified prefix (substring).
   • isalnum()
     • The isalnum() function that checks if all characters in a string are alphanumeric, meaning they are either letters (a-z, A-Z) or numbers (0-9).
   • isalpha()
     • The isalpha() method checks if all characters in a given string are alphabetic.
   • isdigit()
     • The isdigit()used to check if all characters in a string are digits (0-9).
   • isdigit()
     • The isdigit() used to check if all characters in a string are digits (0-9).
   • islower()
     • The islower() method in Python checks if all characters in a string are lowercase
   • isupper()
     • The isupper() method in Python checks if all the alphabetic characters in a string are uppercase.
   • isspace()
     • The isspace() is used to check if all characters in a string are whitespace characters.
   • lstrip()
     • The lstrip() method removes any leading characters (space is the default leading character to remove)
   • rstrip()
     • Iit removes whitespace characters (spaces, tabs, newlines) from the end of the string.
   • strip()
     • To remove leading and trailing characters from a string.
   • replace()
     • The replace() is used to replace occurrences of a specified substring within a string with another substring.
   • join()
     • The join() method in Python is used to concatenate the elements of an iterable (such as a list, tuple, or set) into a single string with a specified delimiter placed between each element.
   • partition()
     • The partition() method splits the string into three parts at the first occurrence of the separator and returns a tuple containing the part before the separator, the separator itself, and the part after the separator.