与回声与返回连接时，句点和逗号之间的区别?
我刚刚发现这行得通:
echo $value , " continue";
但事实并非如此:
return $value , " continue";
虽然."两者都适用.
句号和逗号在这里有什么区别?
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，因此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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