Code-Memo

Comparing Strings

1. Equality Comparison (==):

   str1 = "hello"
   str2 = "hello"
   if str1 == str2:
       print("Strings are equal")
   

2. Inequality Comparison (!=):

   str1 = "hello"
   str2 = "world"
   if str1 != str2:
       print("Strings are not equal")
   

3. Case Sensitivity:

   str1 = "Hello"
   str2 = "hello"
   if str1.lower() == str2.lower():
       print("Case-insensitive comparison: Strings are equal")
   

4. Comparison Operators (<, >, <=, >=):

   str1 = "apple"
   str2 = "banana"
   if str1 < str2:
       print("str1 comes before str2 lexicographically")
   

5. Length Comparison:

   str1 = "apple"
   str2 = "banana"
   if len(str1) < len(str2):
       print("str1 is shorter than str2")
   

String Methods: startswith(), endswith(), and find()

1. startswith(prefix[, start[, end]]):

   • This method checks if a string starts with the specified prefix.
   • Parameters:
     • prefix: Required. The prefix to check against the start of the string.
     • start (optional): Specify where to start the search in the string.
     • end (optional): Specify where to end the search in the string.
   • Returns True if the string starts with prefix, otherwise False.
   • Example:

     text = "Hello, world!"
     if text.startswith("Hello"):
         print("The string starts with 'Hello'")
     

2. endswith(suffix[, start[, end]]):

   • This method checks if a string ends with the specified suffix.
   • Parameters:
     • suffix: Required. The suffix to check against the end of the string.
     • start (optional): Specify where to start the search in the string.
     • end (optional): Specify where to end the search in the string.
   • Returns True if the string ends with suffix, otherwise False.
   • Example:

     filename = "script.py"
     if filename.endswith(".py"):
         print("The file is a Python script")
     

3. find(sub[, start[, end]]):

   • This method searches for the substring sub within the string.
   • Parameters:
     • sub: Required. The substring to search for.
     • start (optional): Specify where to start the search in the string.
     • end (optional): Specify where to end the search in the string.
   • Returns the lowest index in the string where sub is found, or -1 if sub is not found.
   • Example:

     sentence = "Python is powerful"
     index = sentence.find("is")
     if index != -1:
         print(f"'is' found at index {index}")