js - regular expression (part3)

console.log("This is tutorial 48");

// Regular Expressions:

    // Basic functions 

    // Metacharacter Symbols

// const regex = /^h/i;

// Character Sets - We use []

let regex = /h[a-z]rry/; // can be any character from a to z

regex = /h[aty]rry/; // can be an a, t or y

regex = /h[^aty]rry/; // cannot be any of a, t or y

regex = /h[^aty]rr[yYu]/; // cannot be any of a, t or y + can be a u or y

regex = /h[a-zA-Z]rr[yu0-9][0-9]/; // we can have as many character sets as we want

// Quantifiers - We use {}

regex = /har{2}y/; // r can occur exactly 2 times

regex = /har{0,2}y/; // r can occur exactly 0 to 2 (0 or 1 or 2) times

// Groupings  - We use paranthesis for groupings ()

regex = /(har){2}([0-9]r){3}/

// const str = "hirry9 bhai";

str = "harrry bhai"

str = "harhar1r4r5r bhai";

let result = regex.exec(str);

console.log("The result from exec is ", result);

if(regex.test(str)){

    console.log(`The string ${str} matches the expression ${regex.source}`);

}

else{

    console.log(`The string ${str} does not match the expression ${regex.source}`);

}