PHP Reference Book Blog

Thanks to John for submitting this correction!

In the Function Index (pg. 161), array_key_exists() is listed as page 82. However, it is actually on page 79.

Feel free to submit a correction yourself if you find any!

(pg. 38)

In the book, the print_r() function is described as follows:

Output the contents of $variable . Typically used to display the contents of an array.

However, there is also an optional flag for the print_r() function that makes the function return the output rather than printing it to the screen. Therefore, the section of the book should be amended as follows:

return – [optional] $boolean default: FALSE, print output
Output the contents of $variable. Typically used to display the contents of an array. If return is set to TRUE, print_r() returns the output rather than displaying it, such as when storing it in a variable.

(pg. 123)

The function has the following correct syntax:

mysql_result(resource, row[, column])

However, in the explanation paragraph, 2^nd sentence, it uses the term field erroneously instead of the term column. It should read as follows:

If column is specified instead of the value of the
first column, the specified column is retrieved (can be referenced by number
starting with 0 or by name/alias).

It’s the little things, like changing the term used to be clearer to the reader and forgetting to update everything.

(pg. 150)

Book version:

\w – Letter (a-z, A-Z)

Correct version:

\w – Letter, Digit, Underscore [a-zA-Z0-9_]

This is similar to the syntax for alphanumeric: [:alnum:]

(pg. 33)

The description in the book reads:

$_SERVER['QUERY_STRING'] – The current scripts path

This description is the same as the entry above, because I made a bad edit (copy/paste for formatting). The correct description would be as follows:

$_SERVER['QUERY_STRING'] – The current query string (without the question mark)

The example is correct and accurate, and luckily this is painfully obvious thanks to the name of the key QUERY_STRING in the $_SERVER array.