hide - Understanding jQuery

Regular Expressions
How will you know it’s them when you see them?
Regular expressions are common features in computer
languages and text editors. Learning how to use them will
increase your performance as a computer programmer and
problem solver. JavaScript was designed with regex in mind.
The phrase Regular Expression can be shortened. Regular expressions are commonly referred
to as regex, or regexp in conversation. We use regular expressions to find or match a character
pattern within a word or a line of text. For example, we can search for the word clock in the
word clockwork. We can also find the words lock and work in the same word.
lock
clockwork
Regular expressions helps us find words or character patterns inside text and then store the
results in an array for further manipulation or modification. Another important function of
regular expressions lies in their ability to count the number of times a pattern repeats inside a
word or a sentence. For example, there are two o’s in the word clockwork. The following regular
experssion example demonstrates how we can find and count all o’s in the word clockwork:
var pattern = /o/g; // g modifier stands for global search
var result = “clockwork”.match(pattern); // match is a member function of string object
alert(result.count); // display how many times “o” was found
The actual regular expression pattern is stored between two / symbols. But they are not exactly
the same as double quotes when defining a string. The first / explicitly indicates the start of the
pattern whereas the second / explicitly indicates end. It usually matches end of line character.
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