CODEWITHSUNDEEP
regexperl
huang cheng
huang cheng

Reputation: 393

Regular expression for the usage of +

Here is my code. I want to print out all the lines at the beginning of capital:

while(<>){
    if(/^[A-Z][a-z]+/){
        print;
    }
}

test.txt:

Fred
fred
FRED
FreD

After I execute the command:

perl sc.pl test.txt

Fred
FreD

Why the FreD will be printed out? I have use [a-z]+, it seems that the + only match the lower case expect the last one?

Upvotes: 1

Views: 127

Answers (1)

haukex
haukex

Reputation: 3013

The string FreD matches /^[A-Z][a-z]+/ because [A-Z] matches F and [a-z]+ matches re.

To get the desired result, anchor the end of the regex as well: /^[A-Z][a-z]+$/.

See also perlretut.

(Edit: I see now that @Biffen has provided the same answer in the comments, sorry)

Upvotes: 8

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