Week-7-2

Splitting and Joining Strings

Overview of String Manipulation

• Strings can be split into smaller parts using the split method.

• Key concepts: Token and Separator.

  • A token is a substring of a larger string.

  • A separator is a character that divides these tokens in a string.

Splitting Strings

• Example string: music artist song.mp3.

• Separator (slashes) divides the string into parts: music, artist, song.mp3.

• Usage of split:

  • Syntax: string.split(separator).

  • Returns a list of tokens.

Implicit Separator - Whitespace

• Example: When using a string like "I love Python", the default separator is white space.

• Result after split: ['I', 'love', 'Python'].

Splitting URLs

• URL Example: https://example.com/path/to/resource.

• Split by / to get: ['https:', '', 'example.com', 'path', 'to', 'resource'].

• Consecutive slashes yield empty strings.

• A single slash at the beginning or end also yields an empty string.

Joining Strings

• The join method is the opposite of split, used to combine a list of strings.

• Syntax: separator.join(list_of_items).

• Example:

  • Given a list: ['music', 'artist', 'song.mp3']

  • Using join: '/'.join(list_of_items) results in: music/artist/song.mp3.

Joining with a Loop

• Alternative to join: using a for loop.

• Initialize an empty string and add each item in the list together:

  • sentence = ""
    for phrase in phrases:
        sentence += phrase

  • This concatenates without a separator, giving a combined string.

Replacing Separators

• Demonstration of replacing separators:

  • Prompting user for a path and a new separator.

  • Split at the original separator: tokens = original_string.split(original_separator).

  • Join with the new separator: new_string = new_separator.join(tokens).

  • Example: file/path replaced with file\path.

Practical Example

• Changing from Unix-like paths to Windows-type paths: file/path becomes file\path.

Checker for Integer Strings

• Task: Input string should output "yes" if all characters are digits.

• Implementation:

  • Using the isDigit() method to check if all characters are numerical.

  • Code Example:

    input_string = input("Enter a string:")
    if input_string.isdigit():
        print("yes")
    else:
        print("no")

• Example outputs:

  • Input: "145" -> Output: "yes"

  • Input: "1,450" -> Output: "no" (comma is not a digit).

Conclusion

• Understanding split and join methods facilitates string manipulation and management.

• Practical applications include parsing paths and verifying string formats.