string

• Strings in Python are fundamental data structures used to represent sequences of characters.
• They are versatile and can store text, numbers (as text), symbols, and more.
• Single Quotes or Double Quotes
  • You can enclose characters within single (') or double (") quotes to create a string.
  • Both methods are equivalent.

my_string_1 = 'Hello, 🌏!'
my_string_2 = "This is also a string."
string_with_quotes = 'He said, "🙏!"'

my_string_1 = 'Hello, 🌏!' my_string_2 = "This is also a string." string_with_quotes = 'He said, "🙏!"'

• Triple Quotes (Multi-Line Strings)
  • Use triple single (''') or triple double (""") quotes for multi-line strings or strings containing quotes themselves.

multiline_text_1 = """This is a string
that spans multiple lines."""

multiline_text_2 = ''''This is also string
that spans multiple lines.'''

multiline_text_1 = """This is a string that spans multiple lines.""" multiline_text_2 = ''''This is also string that spans multiple lines.'''

• Accessing Characters using Indexing
  • Strings are like sequences (lists) of characters, where each character has an index starting from 0.
  • You can access individual characters using their index within square brackets [].

name = "Chaitanya"
first_letter = name[0]  # 'C'
last_letter = name[-1]  # 'a'

name = "Chaitanya" first_letter = name[0] # 'C' last_letter = name[-1] # 'a'

• Accessing Characters using Slicing
  • You can extract substrings using slicing, which involves specifying a start index (inclusive) and an end index (exclusive) within square brackets [].

greeting = "Hello, 🌏!"
substring = greeting[7:9]  # '🌏!'

greeting = "Hello, 🌏!" substring = greeting[7:9] # '🌏!'

• String Concatenation
  • The + operator combines strings to create a new string.

first_name = "Chaitanya"
last_name = "Reddy"
full_name = first_name + " " + last_name
print(full_name)  # Output: Chaitanya Reddy

first_name = "Chaitanya" last_name = "Reddy" full_name = first_name + " " + last_name print(full_name) # Output: Chaitanya Reddy

• String Formatting with f-strings (Python 3.6+)
  • A concise and powerful way to format strings using f-strings, which embed variables or expressions directly within curly braces {} inside the string.

name = "Chaitanya"
age = 30
message = f"Hi {name}, you are {age} years old."
print(message)  # Output: Hi Chaitanya, you are 30 years old.

name = "Chaitanya" age = 30 message = f"Hi {name}, you are {age} years old." print(message) # Output: Hi Chaitanya, you are 30 years old.

• String Formatting with .format() method (all Python versions)
  • The format() method allows string formatting with placeholders ({}) replaced by arguments.

name = "Chaitanya"
greeting = "Welcome, {}!".format(name)
print(greeting)  # Output: Welcome, Chaitanya!

name = "Chaitanya" greeting = "Welcome, {}!".format(name) print(greeting) # Output: Welcome, Chaitanya!

• Common String Methods
  • len(string): Returns the length (number of characters) in the string.
  • upper(): Converts all characters to uppercase.
  • lower(): Converts all characters to lowercase.
  • strip(): Removes leading and trailing whitespaces.
  • find(substring): Returns the index of the first occurrence of a substring, or -1 if not found.
  • replace(old, new): Replaces all occurrences of a substring with another substring.

line = ' Hi Chaitanya, you are 30 years old'

print(len(line))
print(line.upper())
print(line.lower())
print(line.strip())
print(line.find('30'))
print(line.replace('Chaitanya', 'Chaitu'))

line = ' Hi Chaitanya, you are 30 years old' print(len(line)) print(line.upper()) print(line.lower()) print(line.strip()) print(line.find('30')) print(line.replace('Chaitanya', 'Chaitu'))