PHP

By no means could this appendix replace the value of the PHP manual, but the tables and information listed here might save you a trip online to view it. In this section you'll find lists of

• Operators, comparators, and their precedence

• Date- and time-formatting parameters and functions

• Regular expression characters and classes

• And more!

Operators and comparators

Many of PHP's operators and comparators (symbols used to make comparisons) are self-evident. Still, to be explicit, I've listed most of them in Table B.1. Along with these, don't forget about the variations on the assignment operators: .=, +=, -=, *=, and /=.

Table B.1. PHP's characters for performing operations or making comparisons.

PHP Operators
SYMBOL	MEANING	TYPE
=	is assigned the value of	assignment
==-	is equal to	comparison
!=	is not equal to	comparison
<	less than	comparison
>	greater than	comparison
<=	less than or equal to	comparison
>=	greater than or equal to	comparison
!	is not	logical
&&	and	logical
and	and	logical
||	or	logical
or	or	logical
xor	or not	logical
+	addition	arithmetic
-	subtraction	arithmetic
*	multiplication	arithmetic
/	division	arithmetic
%	modulus	arithmetic
.	concatenation	miscellaneous
++	increment by 1	arithmetic
--	decrement by 1	arithmetic

Table B.2 places most of Table B.1 in order of precedence, from highest (at the top) to lowest. You can memorize this list when writing complex statements or use parentheses to always guarantee the order in which operators will be evaluated.

Operator Precedence

OPERATOR

! ++ --

* / %

+ -.

< <= > >=

== != ===

&&

||

= += -= *= /= .= %=

and

xor

Date and time

After years of programming in PHP, what I still frequently must look up are the formatting parameters used with the date() function. I have recorded most of these in Table B.3. You'll find them in year, month, day, hour, minute, second order, since listing them alphabetically makes it harder to find the formatting you want (check the manual for comparison).

Table B.3. These are the formatting parameters to use with the date() function.

Date() Function Formatting
CHARACTER	MEANING	EXAMPLE
Y	year as 4 digits	2005
y	year as 2 digits	05
n	month as 1 or 2 digits	2
m	month as 2 digits	02
F	month	February
M	month as 3 letters	Feb
j	day of the month as 1 or 2 digits	8
d	day of the month as 2 digits	08
l (lowercase L)	day of the week	Monday
D	day of the week as 3 letters	Mon
w	day of the week as a single digit	0 (Sunday)
z	day of the year: 0 to 365
t	number of days in the given month	31
g	hour, 12-hour format as 1 or 2 digits	6
G	hour, 24-hour format as 1 or 2 digits	18
h	hour, 12-hour format as 2 digits	06
H	hour, 24-hour format as 2 digits	18
i	minutes	45
s	seconds	18
a	am or pm	am
A	AM or PM	PM

As a reminder, the syntax for using the date function is

 date (format, timestamp) 

The function takes the format as a quoted string and can also take an optional timestamp (as an integer). The date() function will return a string value. For example,

 echo date ("F j, Y"); // May 3, 2005 

The geTDate() function, discussed in Chapter 3, "Creating Dynamic Web Sites," returns an array of information for a particular date. The keys and values stored in the array are displayed in Table B.4.

 $date_array = getdate(); 

Table B.4. The array returned by the getdate() function.

The getdate() Array
KEY	MEANING	EXAMPLE
year	year	2005
mon	month	12
month	month name	December
mday	day of the month	25
weekday	day of the week	Tuesday
hours	hours	11
minutes	minutes	56
seconds	seconds	47

This function also takes an optional timestamp.

Regular expressions

In Chapter 10, "Web Application Security," I discussed regular expressions as a means to validate user-submitted form data. Here is a repeat of the three tables listed in that section, with some minor alterations (Tables B.5, B.6, and B.7). These characters are used to establish patterns that will be matched using the ereg(), eregi(), ereg_replace(), and eregi_replace() functions.

Table B.5. These characters have special meanings for regular expressions, although not within classes.

Metacharacters
CHARACTER	MEANING
^	Indicates the beginning of a string
$	Indicates the end of a string
.	Any single character
|	Alternatives (or)
\	Escapes the following character
()	Used for making groups
[]	Used for defining classes

Table B.6. Use these symbols to specify quantities in your regular expressions.

Quantifiers
CHARACTER	MEANING
?	0 or 1
*	0 or more
+	1 or more
{x}	exactly x occurrences
{x, y}	between x and y (inclusive)
{x,}	at least x occurrences

Table B.7. These classes are shorthand for common character sets.

Character Classes
CLASS	MEANING
[a-z]	Any lowercase letter
[a-zA-Z]	Any letter
[0-9]	Any number
[ \f\r\t\n\v]	Any white space
[aeiou]	Any vowel
[[:alnum:]]	Any letter or number
[[:alpha:]]	Any letter (same as [a-zA-Z])
[[:blank:]]	Any tabs or spaces
[[:digit:]]	Any number (same as [0-9])
[[:lower:]]	Any lowercase letter
[[:upper:]]	Any uppercase letter
[[:punct:]]	Punctuation characters (.,;:-)
[[:space:]]	Any white space

Other references

The last set of PHP references I'll include are a grab bag of ideas discussed throughout the book. Table B.8 lists the key-value pairs returned by the getimagesize() function. The most frequently used value is indexed at 3, which is a string used to create the HTML code for the height and width of the image. The third element in the array is a numeric representation of the image type where 1 means GIF, 2 is JPG, 3 PNG, 4 SWF (Shockwave Format), 5 PSD (Photoshop), 6 BMP (Bitmap), 7 and 8, TIFF (two different types), and so on.

Table B.8. The getimagesize() function returns an array with these keys and values.

The getimagesize() Array
ELEMENT	VALUE	EXAMPLE
0	image's width in pixels	423
1	image's height in pixels	368
2	image's type	2 (representing JPG)
3	appropriate HTML img data	height="xx" width="yy"

Finally, Table B.9 displays the contents of the $_FILES array, used when uploading files through the Web browser.

Table B.9. When uploading files, use the $_FILES array to access them.

The $_FILES Array
INDEX	MEANING
name	The original name of the file (as it was on the user's computer)
type	The MIME type of the file, as provided by the browser
size	The size of the uploaded file in bytes
tmp_name	The temporary filename of the uploaded file as it was stored on the server
error	The error code associated with anyproblem in uploading