Basic HTML version of Foils prepared Sept 20 97

Foil 26 Control Structures --
What is true and false?

From Tutorial on PERL Computational Science for Information Age Course CPS616 -- Sept 20 97. by Geoffrey C. Fox,Nancy McCracken,Tom Scavo
1 in PERL all TESTEXPRESSIONs are converted to strings
2 Either the null string or string '0' (same as "0") is evaluated as FALSE
3 Everything else evaluates as TRUE
4 Results of comparison operators are what you expect
  • if ( $age < 18 ) evaluates as TRUE iff the numeric value of $age is less than 18
5 Note the numeric number 0 is converted to "0" and is FALSE as is numeric computation 1-1
6 The string "0.000" evaluates as TRUE
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