October 2005
Intermediate to advanced
372 pages
11h 35m
English
PHP considers some values to be equivalent to true, and others equivalent to false. Most numbers are true (e.g., 1, 59, 1,203,391,462), but 0, 0.0, 0.00000 are all false.
Nearly any string with a value in it is considered to be true, so "a," "193" (an integer inside a string), and "This is a test" are all true. However, an empty string ""and "0" are both false. Confusingly, though, "0.0" is true, as is "0.0000."