How to Split a String into Segments Alternating Letters and Digits Using Regular Expressions?

Splitting a String Between Letters and Digits

When faced with the task of dividing a string into segments marked by alternating letters and digits, programmers may encounter difficulties. Consider the string "123abc345def." It must be split into the following segments: "123," "abc," "345," and "def."

To accomplish this task, regular expressions provide an effective solution. By utilizing a specific pattern, you can partition the string according to the desired criteria. The expression is:

(?<=\D)(?=\d)|(?<=\d)(?=\D)

This pattern identifies positions between a non-digit (D) and a digit (d), as well as positions between a digit and a non-digit.

How it Works:

The pattern consists of two parts separated by the pipe operator (|). Each part matches a specific scenario:

• (?<=D)(?=d): Matches a position where a non-digit is followed by a digit, indicating the transition from a letter to a number.
• (?<=d)(?=D): Matches a position where a digit is followed by a non-digit, indicating the transition from a number to a letter.

Example:

For the string "123abc345def," the above pattern would be matched at the positions:

• Between "123" and "abc"
• Between "abc" and "345"
• Between "345" and "def"

By splitting the string at these positions, the desired segments can be obtained.

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