G'day Don Coyote,

if may be used as a Compound Statement or as a Statement Modifier. It is not an operator.

Placing an if statement in a do block, as you show, can emulate the ternary operator but, as is fairly obvious, results in clunky code with poor readability and maintainability.

So, if introduces a compound statement (or statement modifier) and ?: is an operator. They are not synonymous. With do blocks, parentheses, and other syntactical tricks, you can usually (if not always) replace one with the other; however, this is typically not a good idea. [For more on this, see "Re: Code blocks with ternary operator or trailing conditionals", which I wrote a few weeks ago.]

The ternary operator can be used in any list, not just to generate an array, so an improvement on the print examples you show, might be (using equivalent code):

print 1<2 ? '1' : '2', $/;
[download]

Although, perhaps a more likely scenario might be something like:

$ perl -Mstrict -Mwarnings -e '
    for my $item_count (0..2) {
        print "$item_count item", $item_count == 1 ? "" : "s", ".\n"
    }
'
0 items.
1 item.
2 items.
[download]

When using the ternary operator, take care with precedence issues and add parentheses where needed (the documentation shows some examples).

A final point, unrelated to conditionals, regarding your test:

my $arrref =  \( if(1<2){'1'}else{()} );
[download]

Taking a reference to a list actually returns a list of references to each item in the original list. Accordingly, it would probably be a good idea to avoid any instances of:

$arrayref = \(...);
[download]

While that may work when first written using a list with only one item, any subsequent modifications which result in additional list items will cause problems. A better option would be:

$arrayref = [...];
[download]

Item 2. of "perlref: Making References" has more information on this.

---

---

Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!

Titles consisting of a single word are discouraged, and in most cases are disallowed outright.

Read Where should I post X? if you're not absolutely sure you're posting in the right place.

Please read these before you post! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

Posts may use any of the Perl Monks Approved HTML tags:

a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr

You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)

	For:		Use:
	&		&
	<		&lt;
	>		&gt;
	[		&#91;
	]		&#93;

Link using PerlMonks shortcuts! What shortcuts can I use for linking?

See Writeup Formatting Tips and other pages linked from there for more info.