php check string is contains a substring

Use php to check a string contains substring there maybe many ways, the strpos maybe the most used way, but it’s strange, it not work for me why? That’s what i want to say: the thing you need take care while use strpos .

what’s strpos

Check the php Manual: " strpos — Find position of first occurrence of a string "

int strpos  (  string $haystack  ,  mixed $needle  [,  int $offset = 0  ] )

and for the return value:
"Returns the position as an integer. If needle is not found, strpos() will return boolean FALSE. "

Here is how i use this:

$str = 'google.com';
$find= 'gle.';
if(strpos($str, $find))
{
  echo "find ";
}
else
{
  echo "not find";
}

Run it,it seems works correctly.Do you find the problem? For this sample,It work but let’s try this one:

$str = 'google.com';
$find= 'google.';
if(strpos($str, $find))
{
  echo "find ";
}
else
{
  echo "not find";
}

It’s show "not find", why? the strpos return 0, not 1 . so even the substring found , it’s still show "not find"

the right way for strpos

Since we know strpos will give a numeric value if found else it is null or false,so let’s see the right way:

$str = 'google.com';
$find= 'google.';
if(is_numeric(strpos($str, $find)))
{
  echo "find ";
}
else
{
  echo "not find";
}

Or

$str = 'google.com';
$find= 'google.';
$isfound=strpos($str, $find);
if($isfound!== false)
{
  echo "find ";
}
else
{
  echo "not find";
}

So you know more about strpos now,Happy reading!