How to convert string to boolean php

Question

How can I convert string to boolean    string    false     test mode mail   settype  string   boolean     var dump  test mode mail    if  test mode mail  echo  test mode is on      it returns      boolean true   but it should be boolean false

User · Accepted Answer

Strings always evaluate to boolean true unless they have a value that's considered "empty" by PHP (taken from the documentation for empty):

"" (an empty string);
"0" (0 as a string)

If you need to set a boolean based on the text value of a string, then you'll need to check for the presence or otherwise of that value.

$test_mode_mail = $string === 'true'? true: false;

EDIT: the above code is intended for clarity of understanding. In actual use the following code may be more appropriate:

$test_mode_mail = ($string === 'true');

or maybe use of the filter_var function may cover more boolean values:

filter_var($string, FILTER_VALIDATE_BOOLEAN);

filter_var covers a whole range of values, including the truthy values "true", "1", "yes" and "on". See here for more details.

User · Answer

Edited to show a possibility not mentioned here  because my original answer was far from related to the OP s question   preg match    Is possible to use  However  in most applications it will be much more heavy to use than other answers here   if  preg match   true i    true PHP is a web scripting language of choice           echo   lt br gt  lt br gt Returned true     else       echo   lt br gt  lt br gt Returned False           true     1  i Can also be used if needed in certain situations  It will not return correctly when it evaluates a string containing both  false  and  1

User · Answer

The answer by  GordonM is good  But it would fail if the  string is already true  ie  the string isn t a string but boolean TRUE    which seems illogical   Extending his answer  I d use    test mode mail     string      true  OR  string     true

User · Answer

The String  false   is actually considered a  TRUE  value by PHP  The documentation says      To explicitly convert a value to boolean  use the  bool  or  boolean    casts  However  in most cases the cast is unnecessary  since a value   will be automatically converted if an operator  function or control   structure requires a boolean argument       See also Type Juggling       When converting to boolean  the following values are considered FALSE          the boolean FALSE itself   the integer 0  zero    the float 0 0  zero    the empty string  and the string  0    an array with zero elements   an object with zero member variables  PHP 4 only    the special type NULL  including unset variables    SimpleXML objects created from empty tags         Every other value is considered TRUE  including any resource     so if you do    bool    boolean  False     or   test    false    bool   settype  test   boolean      in both cases  bool will be TRUE  So you have to do it manually  like GordonM suggests

User · Answer

This method was posted by  lauthiamkok in the comments   I m posting it here as an answer to call more attention to it  Depending on your needs  you should consider using filter var   with the FILTER VALIDATE BOOLEAN flag  filter var     true  FILTER VALIDATE BOOLEAN      true filter var      true   FILTER VALIDATE BOOLEAN      true filter var          1  FILTER VALIDATE BOOLEAN      true filter var         1   FILTER VALIDATE BOOLEAN      true filter var        on   FILTER VALIDATE BOOLEAN      true filter var       yes   FILTER VALIDATE BOOLEAN      true  filter var    false  FILTER VALIDATE BOOLEAN      false filter var     false   FILTER VALIDATE BOOLEAN      false filter var          0  FILTER VALIDATE BOOLEAN      false filter var         0   FILTER VALIDATE BOOLEAN      false filter var       off   FILTER VALIDATE BOOLEAN      false filter var        no   FILTER VALIDATE BOOLEAN      false filter var  asdfasdf   FILTER VALIDATE BOOLEAN      false filter var             FILTER VALIDATE BOOLEAN      false filter var       null  FILTER VALIDATE BOOLEAN      false

User · Answer

I was getting confused with wordpress shortcode attributes  I decided to write a custom function to handle all possibilities  maybe it s useful for someone   function stringToBool  str       if  str      true      str      TRUE      str      True      str      on      str      On      str      ON             str   true       else           str   false            return  str    stringToBool  atts  onOrNot

User · Answer

If your  boolean  variable comes from a global array such as   POST and   GET  you can use filter input   filter function    Example for POST    isSleeping    filter input INPUT POST   is sleeping    FILTER VALIDATE BOOLEAN     If your  boolean  variable comes from other source you can use filter var   filter function   Example   filter var  true   FILTER VALIDATE BOOLEAN      true

User · Answer

you can use json decode to decode that boolean   string    false    boolean   json decode  string   if  boolean         Do something   else       Do something else

User · Answer

I do it in a way that will cast any case insensitive version of the string  false  to the boolean FALSE  but will behave using the normal php casting rules for all other strings  I think this is the best way to prevent unexpected behavior    test var    False    test var   strtolower trim  test var       false    FALSE    test var   result    boolean   test var    Or as a function   function safeBool  test var        test var   strtolower trim  test var       false    FALSE    test var      return  boolean   test var

User · Answer

A simple way is to check against an array of values that you consider true    wannabebool    false    isTrue     true  1  yes   ok   wahr     bool   in array strtolower  wannabebool   isTrue

User · Answer

function stringToBool  string       return   mb strtoupper  trim   string       mb strtoupper   true      TRUE   FALSE      or  function stringToBool  string        return filter var  string  FILTER VALIDATE BOOLEAN

User · Answer

You should be able to cast to a boolean using  bool  but I m not sure without checking whether this works on the strings  true  and  false    This might be worth a pop though   myBool    bool  False     if   myBool          do something     It is worth knowing that the following will evaluate to the boolean False when put inside   if      the boolean FALSE itself the integer 0  zero  the float 0 0  zero  the empty string  and the string  0  an array with zero elements an object with zero member variables  PHP 4 only  the special type NULL  including unset variables  SimpleXML objects created from empty tags   Everytyhing else will evaluate to true   As descried here  http   www php net manual en language types boolean php language types boolean casting

User · Answer

Other answers are over complicating things  This question is simply logic question  Just get your statement right    boolString    false    result    true       boolString    Now your answer will be either    false  if the string was  false    or true  if your string was  true     I have to note that filter var   boolString  FILTER VALIDATE BOOLEAN    still will be a better option if you need to have strings like on yes 1 as alias for true

User · Answer

You can use settype method too   SetType  var  Boolean   Echo  var   see 0 or 1

User · Answer

filter var  string  FILTER VALIDATE BOOLEAN  FILTER NULL ON FAILURE     string   1     true  string   1      true  string    true      true  string    trUe      true  string    TRUE      true  string   0     false  string    0      false  string    false      false  string    False      false  string    FALSE      false  string    sgffgfdg      null   You must specify FILTER NULL ON FAILURE otherwise you ll get always false even if  string contains something else

User · Answer

boolean json decode strtolower  string     It handles all possible variants of  string   true     gt  true  True     gt  true  1        gt  true  false    gt  false  False    gt  false  0        gt  false  foo      gt  false           gt  false

User · Answer

the easiest thing to do is this    str    TRUE     boolean   strtolower  str      true    true   false   var dump  boolean     Doing it this way  you can loop through a series of  true    TRUE    false  or  FALSE  and get the string value to a boolean

User · Answer

When working with JSON  I had to send a Boolean value via   POST  I had a similar problem when I did something like   if     POST  myVar      true           do stuff      In the code above  my Boolean was converted into a JSON string   To overcome this  you can decode the string using json decode       assume that     POST  myVar      true    if  json decode  true      true       do your stuff       This should normally work with Boolean values converted to string and sent to the server also by other means  i e   other than using JSON

User · Answer

In PHP you simply can convert a value to a boolean by using double not operator        var dump    true          true var dump     Hello        true var dump    1             true var dump     1  2         true var dump    false         false var dump    null          false var dump                  false var dump    0             false var dump                  false

User · Answer

You can use boolval  strValue   Examples    lt  php echo  0            boolval 0     true     false     n   echo  42           boolval 42     true     false     n   echo  0 0          boolval 0 0     true     false     n   echo  4 2          boolval 4 2     true     false     n   echo               boolval        true     false     n   echo   string      boolval  string      true     false     n   echo   0           boolval  0      true     false     n   echo   1           boolval  1      true     false     n   echo   1  2        boolval  1  2      true     false     n   echo               boolval        true     false     n   echo  stdClass     boolval new stdClass     true     false     n     gt    Documentation http   php net manual es function boolval php

[php] How to convert string to boolean php

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