I noticed that you can do concatenation as a dot, and a comma. But what is the difference between these two operators?

  • An example on ideone is possible? - Qwertiy ♦
  • @Erepaha, just read this php.net/manual/ru/function.echo.php There is an explanation in Russian. - Visman
  • 2
    As soon as you try the "concatenation of a comma" somewhere else, except echo , you will immediately understand the difference ... - Akina

1 answer 1

There is no concatenation separated by a comma in php. What you think of as php.net/manual/ru/function.echo.php for Russian-language documentation is actually the result of translation difficulties. First, notice how the example of using this function is shown:

 void echo ( string $arg1 [, string $... ] )

It clearly shows that the comma acts as a delimiter of arguments.

Secondly, the following is written in the original :

It is not really a need to use parentheses with it . It can not always be used. Additionally, you must not be enclosed within parentheses .

And the translation is this:

In fact, echo is not a function, but a language construct, so it is not necessary to enclose the arguments in brackets . echo (unlike other language constructs) does not behave as a function, therefore it can not always be used in the context of a function. In addition, if you want to pass more than one argument to echo, these arguments cannot be enclosed in brackets .

In my opinion, in the original it is more clear that brackets can be used only if one argument is passed to echo , and in other cases the arguments are passed without brackets separated by commas, which will be the separator of these arguments, and not the concatenation operator.

As a result, you can try to display with the help of this function several variables of different data types and compare what you see with the output result using concatenation.

 echo "test " . true . 1; echo "test " , true , 1;