PHP 中的'print' 和'echo' 之间有什么区别吗？

Is there any difference between 'print' and 'echo' in PHP?

提问by Peter

Possible Duplicate:
How are echo and print different in PHP?

可能的重复：
PHP 中的 echo 和 print 有何不同？

UPDATE :

更新 ：

I found to my relief an exactduplicate(it wasn't showing up when I typed this question at first, I found it with ... google): Please vote with me to close this question, because it's tiring, go hunt that other poor guy a bit ;-)

令我欣慰的是，我发现了一个完全相同的重复项（起初我输入这个问题时它没有出现，我用...谷歌找到了它）：请和我一起投票关闭这个问题，因为它很累，去寻找其他的可怜的家伙有点;-)

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Is there any difference between printand echoin PHP? If so, which should I use and when? If not, why are there two keywords?

PHP 中的print和之间有什么区别echo吗？如果是这样，我应该使用哪个以及何时使用？如果没有，为什么有两个关键字？

UPDATE :

更新 ：

At the downvoters : please read the SO faq. SO was setup also to capture googleable questions. so you shouldn't downvote for that, this question is a valid question, answered on a lot of places and now on SO too.

在投票者中：请阅读 SO 常见问题解答。SO 还设置为捕获可搜索的问题。所以你不应该为此投反对票，这个问题是一个有效的问题，在很多地方都有回答，现在也在 SO 上。

Of course you can downvote for another reason, but please leave a comment in the lines of -1 : downvoted for .. , cause for now, I'm not understanding the downvotes.

当然，您可以出于其他原因投反对票，但请在 -1 行中发表评论：投反对票为 .. ，因为现在，我不理解投反对票。

回答by karim79

From this link, suggested by the PHP manual entry for the echo()function:

从这个链接，该echo()函数的PHP 手册条目建议：

1. Speed. There is a difference between the two, but speed-wise it should be irrelevant which one you use. echo is marginally faster since it doesn't set a return value if you really want to get down to the nitty gritty.

2. Expression. print() behaves like a function in that you can do: $ret = print "Hello World"; And $ret will be

3. That means that print can be used as part of a more complex expression where echo cannot. An example from the PHP Manual:

   $b ? print "true" : print "false";

print is also part of the precedence table which it needs to be if it is to be used within a complex expression. It is just about at the bottom of the precedence list though. Only "," AND, OR and XOR are lower.

3. Parameter(s). The grammar is: echo expression [, expression[, expression] ... ] But echo ( expression, expression ) is not valid. This would be valid: echo ("howdy"),("partner"); the same as: echo "howdy","partner";
   (Putting the brackets in that simple example serves no purpose since there is no operator precedence issue with a single term like that.)

So, echo without parentheses can take multiple parameters, which get concatenated:

echo "and a ", 1, 2, 3; // comma-separated without parentheses
echo ("and a 123"); // just one parameter with parentheses

print() can only take one parameter:

print ("and a 123"); print "and a 123";

1. 速度。两者之间存在差异，但速度方面应该与您使用哪一个无关。echo 稍微快一点，因为如果您真的想深入了解它，它不会设置返回值。

2. 表达。print() 就像一个函数，你可以这样做： $ret = print "Hello World"; 而 $ret 将是

3. 这意味着 print 可以用作更复杂的表达式的一部分，而 echo 不能。PHP手册中的一个例子：

   $b ? 打印“真”：打印“假”；

print 也是优先级表的一部分，如果要在复杂的表达式中使用它，它需要是优先级表的一部分。不过，它位于优先级列表的底部。只有“,” AND、OR 和 XOR 较低。

3. 参数）。语法是：echo expression [, expression[, expression] ... ] 但是echo ( expression, expression ) 无效。这将是有效的： echo ("howdy"),("partner"); 同：echo "howdy","partner";
   （把括号放在那个简单的例子中是没有意义的，因为像这样的单个术语没有运算符优先级问题。）

因此，没有括号的 echo 可以采用多个参数，这些参数会被连接起来：

echo "和", 1, 2, 3; // 逗号分隔，不带括号
echo ("and a 123"); // 只有一个带括号的参数

print() 只能带一个参数：

打印（“和一个 123”）；打印“和一个 123”；

回答by NJChim

some say echo is slightly faster than print since it has no return value. though here is someone who doesn't think the speed difference matters much... http://fabien.potencier.org/article/8/print-vs-echo-which-one-is-faster

有人说 echo 比 print 稍快，因为它没有返回值。尽管这里有人认为速度差异并不重要...... http://fabien.potencier.org/article/8/print-vs-echo-which-one-is-faster

回答by SilentGhost

the answer is in the docs.

答案在文档中。

回答by anddoutoi

print returns, echo does not.

打印返回，回显不返回。

And you are right, totally googleable.

你是对的，完全可以谷歌搜索。