String operations 2 – Python(string)

String are one of the basic data structures and are utilized for a variety of tasks. Here are some of the most commonly used methods and functions for working with strings, along with some examples (Python Document)

1. String Slicing

text = "Hello, Python!"

# Extract the first 5 characters
print(text[:5])  # "Hello"

# Extract a specific range
print(text[7:13])  # "Python"

# Output strings in reverse order
print(text[::-1])  # "!nohtyP ,olleH"

2. Joining strings

# + Combining strings with operators
greeting = "Hello"
name = "Alice"
message = greeting + ", " + name + "!"
print(message)  # "Hello, Alice!"

#Combining strings using join()
words = ["Hello", "Python", "World"]
sentence = " ".join(words)
print(sentence)  # "Hello Python World"

3. Repeating a string

text = "Python"
print(text * 3)  # "PythonPythonPython"

4. Finding the length of a string

text = "Hello, World!"
print(len(text))  # 13

5. Finding a specific character in a string

text = "Hello, Python!"

# 특정 문자 찾기
print(text.find("P"))  # 7 (Where P first appears)
print(text.find("Java"))  # -1 (Returns -1 if it doesn't exist)

# index() throws an error if no character is found
print(text.index("P"))  # 7
# print(text.index("Java"))  # Error occurred

6. Replacing a string

text = "Hello, Python!"
new_text = text.replace("Python", "World")
print(new_text)  # "Hello, World!"

7. Split a string (Split)

text = "apple,banana,cherry"
fruits = text.split(",")
print(fruits)  # ["apple", "banana", "cherry"]

8. Remove spaces in a string

text = "   Hello, World!   "
print(text.strip())  # "Hello, World!"
print(text.lstrip())  # "Hello, World!   "
print(text.rstrip())  # "   Hello, World!"

9. Convert string case

text = "hello, python world"

print(text.upper())  # "HELLO, PYTHON WORLD"
print(text.lower())  # "hello, python world"
print(text.capitalize())  # "Hello, python world"
print(text.title())  # "Hello, Python World"

10. String formatting

name = "Alice"
age = 30

# f-string Formatting
print(f"My name is {name} and I am {age} years old.")

# format() Using methods
print("My name is {} and I am {} years old.".format(name, age))

# % Using operators
print("My name is %s and I am %d years old." % (name, age))

11. String checking (isalpha, isdigit, isalnum)

text = "Hello"
number = "1234"
mixed = "Hello123"

print(text.isalpha())   # True (All Characters)
print(number.isdigit()) # True (All Numbers)
print(mixed.isalnum())  # True (Combinations of letters and numbers)

12. Check if a string contains a specific word

text = "Hello, Python World"
print("Python" in text)  # True
print("Java" in text)    # False