Matching Anything But a Newline
The dot (.) matches anything (except for a newline).
Task
123.456.abc.def
1 | ^(.{3}\.){3}.{3}$ |
Matching Digits & Non-Digit Characters
\d
The expression \d matches any digit [0-9].
\D
The expression \D matches any character that is not a digit.
Task
06-11-2015
1 | (\d){2}(\D){1}(\d){2}(\D){1}(\d){4} |
Matching Whitespace & Non-Whitespace Character
\s
\s matches any whitespace character [ \r\n\t\f ].
\S
\S matches any non-white space character.
For Example
match blank line
1 | \r\n |
Task
12 11 15
1 | (\S){2}(\s){1}(\S){2}(\s){1}(\S){2} |
Matching Word & Non-Word Character
\w
The expression \w will match any word character.
Word characters include alphanumeric characters (a-z, A-Z and 0-9) and underscores (_).
\W
\W matches any non-word character.
Non-word characters include characters other than alphanumeric characters (a-z, A-Z and 0-9) and underscore (_).
Task
www.hackerrank.com
1 | (\w){3}(\W){1}(\w){10}(\W){1}(\w){3} |
Matching Start & End
^
The ^ symbol matches the position at the start of a string.
$
The $ symbol matches the position at the end of a string.
Task
0qwer.
1 | ^(\d){1}(\w){4}(\.){1}$ |