I was doing a hackerrank here and I did the following code:
/^(Mr\.|Mrs\.|Ms\.|Dr\.|Er\.)\w/
But the answer was
/^(Mr\.|Mrs\.|Ms\.|Dr\.|Er\.)\w+$/
and I don't understand the last part of that regex. What is it?
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Super Jade
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mrpepo877
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`\w+$` just means that the pattern ends with any number of characters, while `\w` at the end just means that the thing checked by the pattern is to match a single character, but anything else is allowed after that (in theory). – Tim Biegeleisen Jul 29 '18 at 04:15
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1Try this site for help with regex: https://regexr.com/ It allows you to enter a regex. Then it displays what the regex means. – Super Jade Jul 29 '18 at 04:29
1 Answers
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Here, \w will select An alphanumeric character (“word character”), and When you put a plus sign (+) after something in a regular expression, it indicates that the element may be repeated more than once.
Thus, /\w+/ matches one or more alphanumeric characters.
And $ here means End of string.
Example 1 --- /^(Mr\.|Mrs\.|Ms\.|Dr\.|Er\.)\w$/.test('Mr.J'); // true
Example 2 --- /^(Mr\.|Mrs\.|Ms\.|Dr\.|Er\.)\w$/.test('Mr.Joseph'); // false
Example 3 --- /^(Mr\.|Mrs\.|Ms\.|Dr\.|Er\.)\w+$/.test('Mr.Joseph'); // true
Pawan Singh
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Hi Pawan, your statement is right but i think it misses an imporant thing, using the plus sign forces the element to appear at least once. – AarónBC. Jul 29 '18 at 04:28
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sorry, I missed it, I have Edited my answer. Thanks, @TimBiegeleisen – Pawan Singh Jul 29 '18 at 04:29
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@AarónBC. I think thats what I meant when I said --- Thus, /\w+/ matches one or more alphanumeric characters. Excuse my English but by saying one or more I meant at least once. – Pawan Singh Jul 29 '18 at 04:31