echo, print, print_r differences in PHP

echo, print, print_r differences in PHP

Overview:

All three can output information, but each has its own characteristics:

	Type	Number of output variables	Output Variable Type	return value	Speed
Echo	Language structure	One or more	Simple type variables, such as int, string	No	The fastest
Print	Language structure	One	Simple type variables, such as int, string	Int	Fast
Print_r	Function	One	Complex types, such as arrays, objects	bool	Slow

Echo is not a function, but a PHP statement that can output multiple variables with a comma interval and has no return value, which is also the fastest.

 
  echo "Xyw_", "Eliot", "Blog"; Output Xyw_eliot Blogecho ("Xyw_", "Eliot", "Blog");//Compile error, parentheses cannot pass multiple parameters $name = "Xyw_eliot"; echo "$name is a blog!"; /Output Xyw_eliot is a Blog!echo ' $name is a blog! '; /Output $name is a blog!//double quotation marks will parse the internal variables, output the contents of the variables, and the single quotation marks will not parse the variables, but output them as-is?>

The use of print and Echo is basically the same, but print can only output one variable and has a return value that returns 1 if the output succeeds.

 
  Print "Xyw_eliot is a blog!\n";//Output Xyw_eliot is a blog!//print "Xyw_eliot", "is a blog!"; /Compile error, print cannot pass multiple parameters $return = print "Xyw_eliot is a blog!\n";//print successfully, return 1echo $return;//Output 1?>

Print_r is a function that prints easy-to-understand information about variables. If the argument is a string, integer, or float, the variable value itself is printed. If the parameter is an array, the keys and elements are displayed in a certain format. object is similar to an array.

Print_r has two parameters, the first is a variable, the second can be set to true, and if set to True, returns the variable to be printed, otherwise returns a Boolean value of true.

 
  "Xyw", "2" = "Eliot", "3" = "blog");p Rint_r ($arr);//output array $return =print_r ($arr);//return value is 1echo $return;//Output 1$ Return =print_r ($arr, true);//return array echo $return;//output Array?>

Output:

Array
(
[1] = Xyw
[2] = Eliot
[3] = = Blog
)

This article is Eliot original, reprint please indicate source: http://blog.csdn.net/xyw_blog/article/details/13743341

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