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.