PHP true & 'true' difference

Question

Quick question. Is there a difference between

$success = true;

and

$success = \'true\';

I know they are n

Answer 1

Any non-empty string evaluates to true and an empty string evaluates to false. The following script might shed some light for you:

';

if('false' == true) {
  echo "'false' == true";
} else {
  echo "'false' != true";
}

echo '
';

if('foo' == true) {
  echo "'foo' == true";
} else {
  echo "'foo' != true";
}

echo '
';

if('false' == false) {
  echo "'false' == false";
} else {
  echo "'false' != false";
}

echo '
';

if('' == true) {
  echo "'' == true";
} else {
  echo "'' != true";
}

echo '
';

if('' == false) {
  echo "'' == false";
} else {
  echo "'' != false";
}

?>

Here is the output:

'true' == true
'false' == true
'foo' == true
'false' != false
'' != true
'' == false

As requested, here are some more examples comparing == with === for various values.

'true' vs. true
";

if('true' == true) {
  echo "'true' == true
";
} else {
  echo "'true' != true
";
}

if('true' === true) {
  echo "'true' === true
";
} else {
  echo "'true' !== true
";
}

echo "
'false' vs. true
";

if('false' == true) {
  echo "'false' == true
";
} else {
  echo "'false' != true
";
}

if('false' === true) {
  echo "'false' === true
";
} else {
  echo "'false' !== true
";
}

echo "
1 vs. true
";

if(1 == true) {
  echo "1 == true
";
} else {
  echo "1 != true
";
}

if(1 === true) {
  echo "1 === true
";
} else {
  echo "1 !== true
";
}

echo "
0 vs. false
";

if(0 == false) {
  echo "0 == false
";
} else {
  echo "0 != false
";
}

if(0 === false) {
  echo "0 === false
";
} else {
  echo "0 !== false
";
}

echo "
1 vs. 'true'
";

if(1 == 'true') {
  echo "1 == 'true'
";
} else {
  echo "1 != 'true'
";
}

if(1 === 'true') {
  echo "1 === 'true'
";
} else {
  echo "1 !== 'true'
";
}

echo "
empty string '' vs. false
";

if('' == false) {
  echo "'' == false
";
} else {
  echo "'' != false
";
}

if('' === true) {
  echo "'' === false
";
} else {
  echo "'' !== false
";
}

?>

Output:

'true' vs. true

'true' == true
'true' !== true

'false' vs. true

'false' == true
'false' !== true

1 vs. true

1 == true
1 !== true

0 vs. false

0 == false
0 !== false

1 vs. 'true'

1 != 'true'
1 !== 'true'

empty string '' vs. false

'' == false
'' !== false