<？php，<？，<？=，有什么不同？ [重复]

Question

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Reference - What does this symbol mean in PHP?

I don't know if this has been asked before, but here goes: What's the difference between <?php, <?=, and <??
I'm just curious, and people have been telling me to use <?php instead of <?, but I just use <? because it works for me and it's faster. I ain't seein' no diff'rence (redneck accent for extra pleasures...).

Answer 1

<?php and <? are equivalent, except it's generally preferred to use <?php since not every server configuration may have the short opening PHP tags option enabled.

<?= is a shortcut for echoing back the value of a variable/expression, i. e.

<?=$var ?>

is similar to

<?php echo $var; ?>