What s the difference between echo print and print r in PHP

Question

I use echo and print r much  and almost never use print   I feel echo is a macro  and print r is an alias of var dump   But that s not the standard way to explain the differences

User · Answer

they both are language constructs  echo returns void and print returns 1  echo is considered slightly faster than print

User · Answer

echo   Outputs one or more strings separated by commas No return value  e g  echo  String 1    String 2    print   Outputs only a single string Returns 1  so it can be used in an expression  e g  print  Hello   or  if   expr  amp  amp  print  foo     print r     Outputs a human-readable representation of any one value Accepts not just strings but other types including arrays and objects  formatting them to be readable Useful when debugging May return its output as a return value  instead of echoing  if the second optional argument is given   var dump     Outputs a human-readable representation of one or more values separated by commas Accepts not just strings but other types including arrays and objects  formatting them to be readable Uses a different output format to print r    for example it also prints the type of values Useful when debugging No return value   var export     Outputs a human-readable and PHP-executable representation of any one value Accepts not just strings but other types including arrays and objects  formatting them to be readable Uses a different output format to both print r   and var dump   - resulting output is valid PHP code  Useful when debugging May return its output as a return value  instead of echoing  if the second optional argument is given   Notes    Even though print can be used in an expression  I recommend people avoid doing so  because it is bad for code readability  and because it s unlikely to ever be useful    The precedence rules when it interacts with other operators can also be confusing   Because of this  I personally don t ever have a reason to use it over echo  Whereas echo and print are language constructs  print r   and var dump   var export   are regular functions   You don t need parentheses to enclose the arguments to echo or print  and if you do use them  they ll be treated as they would in an expression   While var export   returns valid PHP code allowing values to be read back later  relying on this for production code may make it easier to introduce security vulnerabilities due to the need to use eval     It would be better to use a format like JSON instead to store and read back values   The speed will be comparable

User · Answer

Echo     It is statement not a function No return value   Not Required the parentheses  Not Print Array  Print   It is real function  Return type 1  Required the Parentheses  Not Print Array  Print r  Print in human readable format  String not in Quotes  Not Detail Information of Variable like type and all  var dump  All dump information of variable like type of element and sub element

User · Answer

print and echo are more or less the same  they are both language constructs that display strings  The differences are subtle  print has a return value of 1 so it can be used in expressions whereas echo has a void return type  echo can take multiple parameters  although such usage is rare  echo is slightly faster than print   Personally  I always use echo  never print    var dump prints out a detailed dump of a variable  including its type and the type of any sub-items  if it s an array or an object   print r prints a variable in a more human-readable form  strings are not quoted  type information is omitted  array sizes aren t given  etc   var dump is usually more useful than print r when debugging  in my experience  It s particularly useful when you don t know exactly what values types you have in your variables  Consider this test program    values   array 0  0 0  false        var dump  values   print r   values     With print r you can t tell the difference between 0 and 0 0  or false and      array 4       0   gt    int 0     1   gt    float 0     2   gt    bool false     3   gt    string 0        Array        0    gt  0      1    gt  0      2    gt        3    gt

User · Answer

echo   echo is a language construct where there is not required to use parentheses with it and it can take any number of parameters and return void      void echo  param1 param2 param3            Example  echo  test1   test2 test3     print   it is a language construct where there is not required to use parentheses it just take one parameter and return      1 always              int print param1               print  test1              print  test1   test2      It will give syntax error   prinf   It is a function which takes atleast one string and format style and returns length of output string        int printf  string  s         s   Shailesh        i  printf  Hello  s how are you    s           echo  i       Output   Hello Shailesh how are you               27       echo returns void so its execution is faster than print and printf

User · Answer

The difference between echo  print   print r and var dump is very simple       echo    echo is actually not a function but  a language construct which is used to print output  It is marginally faster than the print   echo  Hello World         this will print Hello World echo  Hello    World      Multiple arguments - this will print Hello World   var 1 55  echo   var 1                    this will print 55 echo  var 1    var 1            this will print var 1 55 echo 45  var 1                  this will print 100   var 2  PHP   echo   var 2                        this will print PHP   var 3 array 99 98 97               Arrays are not possible with echo  loop or index  value required   var 4 array  P   gt  3   J   gt  4       Arrays are not possible with echo  loop or index  value required    You can  also use  echo statement with or without parenthese  echo   Hello World         this will print Hello World      print   Just like echo construct print is also a language construct and not a real function  The  differences between echo  and print is  that  print  only accepts a single argument and print always returns 1  Whereas echo has no return value  So print statement can be used  in expressions    print  Hello World         this will print Hello World print  Hello    World      Multiple arguments - NOT POSSIBLE with print  var 1 55  print   var 1                    this will print 55 print  var 1    var 1            this will print var 1 55 print 45  var 1                  this will print 100   var 2  PHP   print   var 2                        this will print PHP   var 3 array 99 98 97               Arrays are not possible with print  loop or index  value required   var 4 array  P   gt  3   J   gt  4       Arrays are not possible with print  loop or index  value required    Just like echo   print  can be used with or without parentheses   print   Hello World         this will print Hello World      print r     The print r   function is used to print human-readable information about a variable   If the argument is an array  print r   function  prints its keys and elements  same for objects    print r   Hello World          this will print Hello World   var 1 55  print r    var 1                     this will print 55 print r   var 1    var 1             this will print var 1 55 print r  45  var 1                   this will print 100   var 2  PHP   print r    var 2                      this will print PHP   var 3 array 99 98 97                 this will print Array    0    gt  1  1    gt  2  2    gt  3     var 4 array  P   gt  3   J   gt  4         this will print  Array    P    gt  3  J    gt  4         var dump    var dump function usually used for debugging and prints the information   type and value  about a variable array object    var dump  var 1          this will print  int 5444   var dump  var 2          this will print  string 5   Hello   var dump  var 3          this will print  array 3     0   gt  int 1   1   gt  int 2   2   gt  int 3     var dump  var 4          this will print  array 2      P    gt  string 1   3    J    gt  string 1   4

User · Answer

Just to add to John s answer  echo should be the only one you use to print content to the page   print is slightly slower  var dump   and print r   should only be used to debug   Also worth mentioning is that print r   and var dump   will echo by default  add a second argument to print r   at least that evaluates to true to get it to return instead  e g  print r  array  TRUE    The difference between echoing and returning are    echo  Will immediately print the value to the output  returning  Will return the function s output as a string  Useful for logging  etc

User · Answer

Echocan accept multiple expressions while print cannot    The Print r    PHP function is used to return an array in a human readable form  It is simply written as     Print r   your array   1

User · Answer

print r   can print out value but also if second flag parameter is passed and is TRUE - it will return printed result as string and nothing send to standard output  About var dump  If XDebug debugger is installed so output results will be formatted in much more readable and understandable way

User · Answer

print r   is used for printing the array in human readable format

User · Answer

echo   Not having return type    print   Have return type  print r     Outputs as formatted

[php] What's the difference between echo, print, and print_r in PHP?

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