CODEWITHSUNDEEP
perlconditional-operatorcomma-operator
user959408
user959408

Reputation:

Perl period vs comma operator

Why does

print "$str is " , ispalindrome($str) ? "" : " not" , " a palindrome\n"

print "madam is a palindrome", but

print "$str is " . ispalindrome($str) ? "" : " not" . " a palindrome\n"

prints ""?

Upvotes: 9

Views: 1045

Answers (1)

jwodder
jwodder

Reputation: 57610

The conditional operator (? :) has higher precedence than the comma, but lower than the period. Thus, the first line is parsed as:

print("$str is " , (ispalindrome($str) ? "" : " not"), " a palindrome\n")

while the second is parsed as:

print(("$str is " . ispalindrome($str)) ? "" : (" not" . " a palindrome\n"))

Upvotes: 20

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