Regex match only if string contains what is specified but nothing else-CodePudding

I'm trying to implement a REGEX in perl that matches if the string contains anything I specify, but it must fail if the string contains anything else even if it contains my regex elements in addition. For instance:

if ($string !~ m/[ACTG]{1,}/) {
  die "invalid sequence";
}

If I input DQJ as s sequence, the program dies. However, if I input ACH it doesn't since it contains at least one element from the regex pattern.

I would like the match to fail if the string contains anything other than A, C, T or G.

PS: I am unfamiliar with the nomenclature in this case, what would I call what is inside // in the regex statement?

CodePudding user response：

You can make sure every character is a valid character.

die if !/^[ACTG]*\z/;

Using the faster tr///:

die if tr/ACTG// != length($_);

Or you can make sure the string doesn't contain an invalid character.

die if /[^ACTG]/;

Using the faster tr///:

die if tr/ACTG//c;

Thanks to @DavidO for suggesting tr///.

CodePudding user response：

Use the ^ character to define the beginning of the string and the $ to define the end.

if ($string !~ /^[ACTG]*$/){die "invalid sequence";}