This is fairly easy to do if you use regular expressions. It makes working with the data much easier.įor validators, you can either raise an error to the user that the input needs to be entered in a certain format or you can write a function that will take the user’s input and save it in the format you’d like. When working with databases, it’s important to have the same format for all the fields. You can use regex to write a function that makes certain that the input from the user is in the format we want. Take, for instance, when a user inputs a phone number into a form. This is an optimal time to make sure a user is giving you the proper format for their input fields. When we validate, we want to make sure it follows the correct format. The other way to use regular expressions is to validate something. If it does not, we can replace it with something else - either a null value or something of your choosing to indicate that the email is incorrect. If we are unsure as to whether or not all of the addresses are valid email addresses, we can use regex methods to make sure it has the correct format. Now imagine having 1,000 of those fields! It would be too timely to check over each record by hand. Let’s say we have a customer database that has some email address for each customer: Sample Customer Database you take a quick look at the database, you can see there are some typos in the email field. The first use case for using regular expressions would be if you want to search for a particular pattern and then replace it with something else.
Depending on the circumstances, you can test your regex pattern in a number of different ways. What are Regular Expressions Used for?Ī Regular Expression is useful when you need to search and replace a pattern in a string, and when you need to validate a form.
The methods in Java are fairly similar to those found in other languages as well.
This means that the pattern in Java is most likely the same in JavaScript or Ruby. The actual metacharacters used to build a regular expression are fairly language agnostic for those languages that support using it. What are Regular Expressions?Īt a very high level, regular expressions are just pattern matchers - characters that match a pattern.
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