RegExp

Question 0

Regexp:

Form a regex express to find the year in the string Jan 8, 1998.

Answer 0

\d{4}

\d finds only digits 0-9 and {n} is a quantifier saying how many repetitions to find.

Question 1

Regexp:

What character is used to declare a regex expression?

Answer 1

/

Question 2

Regexp:

What is the metacharacter that means the same thing as the quantifier {1,} ?

Answer 2

+

exp+ looks for one or more matches.

Question 3

Regexp:

What will the expression /(\w)\1/ search for?

Answer 3

2 repeating word characters.

It is similar to /[a-zA-Z0-9]{2}/ only it remembers the searched character in a group.

Question 4

Regexp:

In the expression /(n|z)it/g what does the g mean?

Answer 4

Global

The expression will find every nit or zit in the string not just the one.

String.match ignores the global flag and only find the first match.

Question 5

Regexp:

What does \D search for?

Answer 5

Everything that is not a digit, [^0-9].

Question 6

Regexp:

regexp.exec(string) is a slightly more powerful version of which string method?

Answer 6

String.match( )

Regexp.exec is more powerful because the array it returns all the pattern matching information for each match.

• the matched text
• the values of the subexpression in parentheses
• the index of the matched text
• the original input string

Question 7

Regexp:

Which regexp anchor allows you specify all the non-word characters between words?

Answer 7

\b

\b or word boundaries match the position between a \w character and a \W character. They value of \b is NOT returned as part of the match.

Question 8

Regexp:

Make a pattern that finds all instances of the for “it” independent of capitalization, where “it” is not part of another word.

Answer 8

/\bit\b/gi