与 echo 与 return 连接时句号和逗号之间的区别? [英] Difference between period and comma when concatenating with echo versus return?

问题描述

我刚刚发现这会起作用:

I just found that this will work:

echo $value , " continue";

但这不会:

return $value , " continue";

虽然."两者都适用.

这里的句号和逗号有什么区别?

What is the difference between a period and a comma here?

推荐答案

return 只允许一个表达式.但是 echo 允许一个表达式列表，其中每个表达式用逗号分隔.但请注意，由于 echo 不是函数而是一种特殊的语言结构，将表达式列表括在括号中是非法的.

return does only allow one single expression. But echo allows a list of expressions where each expression is separated by a comma. But note that since echo is not a function but a special language construct, wrapping the expression list in parenthesis is illegal.

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