Chapter 7. Practical PHP
The previous chapters went over the elements of the PHP language. This chapter builds on your new programming skills to teach you how to perform some common but important practical tasks. You will learn the best ways to handle strings in order to achieve clear and concise code that displays in web browsers exactly how you want it to, including advanced date and time management. You’ll also find out how to create and otherwise modify files, including those uploaded by users.
Using printf
You’ve already seen the print
and echo
functions, which simply output text to the browser. But a much more powerful function, printf
, controls the format of the output by letting you put special formatting characters in a string. For each formatting character, printf
expects you to pass an argument that it will display using that format. For instance, the following example uses the %d
conversion specifier to display the value 3
in decimal:
printf("There are %d items in your basket", 3);
If you replace the %d
with %b
, the value 3
will be displayed in binary (11
). Table 7-1 shows the conversion specifiers supported.
Specifier | Conversion action on argument arg | Example (for an arg of 123) |
---|---|---|
% |
Display a % character (no arg required) |
% |
b |
Display arg as a binary integer |
1111011 |
c |
Display ASCII character for arg |
{ |
d |
Display arg as a signed decimal integer |
123 |
e |
Display arg using scientific notation |
1.23000e+2 |
f |
Display ... |
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