Weak typing in PHP: why use isset at all?

by 
if ($tx)

This code will evaluate to false for any of the following conditions:

unset($tx); // not set, will also produce E_WARNING
$tx = null;
$tx = 0;
$tx = '0';
$tx = false;
$tx = array();

The code below will only evaluate to false under the following conditions:

if (isset($tx))

// False under following conditions:
unset($tx); // not set, no warning produced
$tx = null;

For some people, typing is very important. However, PHP by design is very flexible with variable types. That is why the Variable Handling Functions have been created.

More Related Contents:

  1. Parse error: syntax error, unexpected ‘else’ (T_ELSE) in C:\xampp3\htdocs\wb_html\login.php on line 8 [duplicate]
  2. Parse error: syntax error, unexpected ‘;’ [closed]
  3. What is the difference between single-quoted and double-quoted strings in PHP?
  4. PHP syntax for dereferencing function result
  5. What are the PHP operators “?” and “:” called and what do they do?
  6. Special characters in property name of object
  7. Difference between if () { } and if () : endif;
  8. What is the meaning of three dots (…) in PHP?
  9. PHP curly brace syntax for member variable
  10. PHP Difference between array() and []
  11. Difference between period and comma when concatenating with echo versus return?
  12. Why are functions and methods in PHP case-insensitive?
  13. Shorthand for arrays: is there a literal syntax like {} or []?
  14. What does ${ } mean in PHP syntax?
  15. Double underscore in PHP
  16. What does ? … : … do? [duplicate]
  17. What is the difference between the PHP open tags “
  18. What is “:” in PHP? [closed]
  19. What does the b in front of string literals do?
  20. PHP syntax for dereferencing function result
  21. Why PHP variables start with a $ sign symbol?
  22. PHP – Returning the last line in a file?
  23. Difference between
  24. How can I add a condition inside a php array?
  25. What is the difference between ‘ and ” in PHP? [duplicate]
  26. syntax error, unexpected T_ENCAPSED_AND_WHITESPACE, expecting T_STRING or T_VARIABLE or T_NUM_STRING [duplicate]
  27. What is the name for the “
  28. Where can I read about conditionals done with “?” and “:” (colon)? [duplicate]
  29. What is the use of
  30. default as first option in switch statement?

Leave a Comment