(jeffa) Re: What does the ternary statement actually do?

It is simply a quick and dirty if-else statement:

return $is_true ? 'is true!' : 'is false';

# is just a one line way of saying
if ($is_true) {
  return 'is true!';
}
else {
  return 'is false!';
}
[download]

Let me elaborate a bit more (aka update):
You can even nest them:

$a = $is_true ? 'is true!' : $was_true ? 'was true' : 'was never true'
+;
[download]

$a will contain one of the strings depending upon the value of $is_true and $was_true.

The 'hook' operator (as i like to call it) is best used for assignments, as my examples showed. Don't be tempted to do this, as it is just bad coding practice:

$some_boolean ? do_sub1() : do_sub2();
[download]

--------------------------------------------------

perl -le '$x="jeff";$x++ for(0..4482550);print $x'

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Re: (jeffa) Re: What does the ternary statement actually do? by dmmiller2k (Chaplain) on Aug 13, 2001 at 23:01 UTC
At the risk of beating a dead horse: The ternary expression is an expression, whereas the `if` equivalent is a statement. In even more other words, the `if` statement cannot be used as a component of an expression while the ternary operator can. So, this: `my $x = $is_true ? 'is true!' : 'is false';` may be considered a shorter way of saying this (note that the `my $x;` must appear outside of the `if`): `my $x; if ($is_true) { $x = 'is true!'; } else { $x = 'is false!'; }` [download] But, one cannot always simply condense an arbitrary `if` statement into a ternary expression -----[ BofA: 212 583-8077 David.Miller(AT)bofasecurities(DOT)com ]----- David M. Miller \| phone/FAX: 212 662-0715 Business Visions, Inc., Suite #8E \| cell: 917 952-1600 680 West End Ave, New York, NY 10025 \| e-mail: dmmiller(AT)acm(DOT)org --------------------------------------+-------------------------------- Spam Resistant (replace '(AT)' => '@', and '(DOT)' => '.')	[reply] [d/l] [select]

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Re: (jeffa) Re: What does the ternary statement actually do?
by dmmiller2k (Chaplain) on Aug 13, 2001 at 23:01 UTC

At the risk of beating a dead horse:

The ternary expression is an expression, whereas the if equivalent is a statement.

In even more other words, the if statement cannot be used as a component of an expression while the ternary operator can.

So, this:

my $x = $is_true ? 'is true!' : 'is false';

may be considered a shorter way of saying this (note that the my $x; must appear outside of the if):

my $x;
if ($is_true) {
  $x = 'is true!';
}
else {
  $x = 'is false!';
}
[download]

But, one cannot always simply condense an arbitrary if statement into a ternary expression

-----[ BofA: 212 583-8077 David.Miller(AT)bofasecurities(DOT)com ]-----
David M. Miller                       | phone/FAX:         212 662-0715
Business Visions, Inc., Suite #8E     | cell:              917 952-1600
680 West End Ave, New York, NY  10025 | e-mail: dmmiller(AT)acm(DOT)org
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