Gain insights into regular expressions' utility for text manipulation. Learn about efficient searching and replacing commands to enhance productivity in daily programming tasks.

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Ever wondered how the search or replace button works? They are very useful commands. 

For beginners and professionals alike, we use these commands in our day-to-day work life, at least once a day. This is why I felt the need to build a course that could help you increase your knowledge and save time while working with strings or any sort of text.

The objective of this course is to help you get a strong grip on regular expressions, or in shorthand, regex. Instead of writing repetitive tasks, it mainly focuses on efficient searching in text files.

Regular Expressions for Programmers

# Overview of quantified character

Let's consider the problem we were working on in the [previous lesson](https://www.educative.io/courses/regular-expressions-programmers/repetition-character#requirement-of-repetition-character). You can re-write the RegEx as `/\(\d+\)-\(\d+\)-\(\d+\)/`. This way, the RegEx was shortened and much easier to understand. In this RegEx, it will have at least one occurrence of the number character set. However, this would match the five-digit number as well. How do we mention it a specific number of times? RegEx utilizes the quantified character to overcome this problem.


# Usage of quantified character

If you want the specific number of times, then there is a range {min, max}, which is written using curly braces that provides the minimum and maximum times allowed. the minimum number is required whereas the maximum is optional.

# Ways to write quantified repetition

* `/{min,max}/` at-least and at-max occurrence of preceding character.
* `/{min}/` minimum and maximum are the same, which means the exact number of times of preceding character.
* `/{min,}/` at least occurrence of preceding character.

Negative numbers are not allowed inside `"{}"` curly braces.

Now, the problem is solved. You can use quantified repetition characters to avoid text like "goood" and any five-digit combination.
Your RegEx will become `/\(\d{4}\)-\(\d{3}\)-\(\d{3}\)/`. The RegEx engine will match parentheses and any four-digit combination of numbers, neither less than four nor greater than four. Exactly the four-digits. In a another group, the same thing would occur.

Learn about the quantified character in RegEx.

Introduction to RegEx

Characters

Character Set

Repetition Character

Grouping and Alteration Character

Anchor Character

Concepts about RegEx

Conclusion

Assessment 1

Quantified Character

Overview of quantified character