I have two strings to compare.

  1. String 1 consists of a mix of 3 characters, a, b & c. Eg. AABCBAABCCCCAB
  2. String 2 consists of a mix pf 2 characters; a & b.Eg. AABABAABABABAB

I need to determine if string 2 contains As everywhere there is an A in string 1; and Bs wherever string 1 contains Bs. I don't care what string 2 contains where string 1 contains Cs.

All I need is a boolean result whether string 2 'matches' string 1. (The above example is a 'match'.)

If it helps, the choice of the 3 characters used is open to change.

The strings can be quite long and there are lots of string 2s to be compared against each string 1; so I'd rather avoid a byte by byte (at the Perl level) comparison.

I think it ought to be possible to get my boolean using some combination of byte-wise boolean string ops; but I haven't hit on which?

Update: The above two samples match because:

AABCBAABCCCCAB
AABABAABABABAB
AAB BAAB    AB  ## I don't care what's in string 2 where there is a C 
+in string 1.

[download]

Update2: Solution

Solved it with:

$ab  = "AABABAABABABAB";;

$abmatch = "AABABAABABABAB";;
print +(( $abc & $abmatch ) eq $abmatch) ? 'yes' : 'no';;
yes

$abnomatch = "ABBABAABABABAB";;
print +(( $abc & $abnomatch ) eq $abmatch) ? 'yes' : 'no';;
no

[download]
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In reply to Tri state string compare? (Solved! see update2) by BrowserUk

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