How to compare strings case-sensitively?

Question

The name variable may contain 2 words: template or TEMPLATE. Comparing both words (template and TEMPLATE) to "template" string gives TRUE. For example, the code:

...
@name = split(/_/,$f,2);
print("$name[0]");
if ("$name[0]" == "template"){
    print ("\n lowercase \n"); 
} elsif ("$name[0]" == "TEMPLATE") {
    print ("\n UPPERCASE \n");
}

Results:

template

lowercase

TEMPLATE

lowercase

How to compare strings case-sensitively? Really appreciate your help.

@Halona *Always* `use strict; use warnings;`! And compare strings with `eq`, not `==`. — Biffen, Mar 18 '15 at 10:41
possible duplicate of [perl string compare with "eq" vs "=="](http://stackoverflow.com/questions/14046669/perl-string-compare-with-eq-vs) — Biffen, Mar 18 '15 at 10:55

score 4 · Accepted Answer · edited Mar 18 '15 at 11:34

4

In perl, the == operator is used to make numeric comparisons, while the eq operator is used to make string comparisons.

If $name[0] contains TEMPLATE then this:

($name[0] == "template")

is equivalent to comparing 0 with 0, since a string containing non-numeric data will be co-erced to 0 in a numeric context.

If you run it with warnings (use warnings; at the top of the script) you will see warnings about that.

If you want a case sensitive comparison it is enough to use:

($name[0] eq "template")

As a side issue there is no need to write the LHS as "$name[0]" as you have done.

edited Mar 18 '15 at 11:34

Daniel Böhmer

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answered Mar 18 '15 at 10:54

harmic

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Thank you hamic. Can you please explain what is "LHS"? I could not translate it.. – Halona Mar 18 '15 at 10:57
2

LHS = Left hand side, I mean, you do not need the quotes around the variable. The quotes would only be needed if you wanted to insert the variable into some other text. – harmic Mar 18 '15 at 10:58

How to compare strings case-sensitively?

1 Answers1