I was taking a look at this response from @Sergio here on the stackoverlow:
There was a snippet of code like this:
/^(\d)+$/.test(111)
What exactly does do in this regular expression?
I was taking a look at this response from @Sergio here on the stackoverlow:
There was a snippet of code like this:
/^(\d)+$/.test(111)
What exactly does do in this regular expression?
If you have one or more capture groups in the regex this will fetch the value captured in the first group. As that a variable that assumes the value of the group. If there is more than one you can use
, etc.
For example:
/^(\w)(\d)$/
accepts strings with two equal letters followed by two equal numbers two to two.
For example aa11
or bb33
( example ).
/^(\w)(\d)$/
looks like the above example but accepts merged patterns.
For example a1a1
or b3b3
( example ).
It is the result of the first group that is represented by ( )
, so bar number ( ) get the value of it. Other languages use dollar sign, ex:
$1
.
Regular expressions have daytime utilities, say you have a text file full of inserts where dates are in dd/mm/yyyy
format with a suitable editor you can convert to yyyy-mm-dd
with replace.
10/23/2015
Use ([0-9]{2})\/([0-9]{2})/([0-9]{4})
to caputrar the date and This will change the position of the year for the day, then it is only to change the separator from
\
to -
and date will be 2015-10-23. / p>