1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
|
<?xml version="1.0" encoding="UTF-8"?>
<!-- Reviewed: no -->
<sect1 id="zend.date.basic">
<title>Basic Methods</title>
<para>
The following sections show basic usage of <classname>Zend_Date</classname> primarily by
example. For this manual, "dates" always imply a calendar date with a time, even when not
explicitly mentioned, and vice-versa. The part not specified defaults to an internal
representation of "zero". Thus, adding a date having no calendar date and a time value of 12
hours to another date consisting only of a calendar date would result in a date having that
calendar date and a time of "noon".
</para>
<para>
Setting only a specific date, with no time part, implies a time set to 00:00:00. Conversely,
setting only a specific time implies a date internally set to 01.01.1970 plus the number of
seconds equal to the elapsed hours, minutes, and seconds identified by the time. Normally,
people measure things from a starting point, such as the year 0 A.D. However, many software
systems use the first second of the year 1970 as the starting point, and denote times as a
timestamp offset counting the number of seconds elapsed from this starting point.
</para>
<sect2 id="zend.date.basic.creation">
<title>Current Date</title>
<para>
Without any arguments, constructing an instance returns an object in the default locale
with the current, local date using <acronym>PHP</acronym>'s
<methodname>time()</methodname> function to obtain the <ulink
url="http://en.wikipedia.org/wiki/Unix_Time">UNIX timestamp</ulink>
for the object. Make sure your <acronym>PHP</acronym> environment has the correct
<link linkend="zend.date.setdefaulttimezone">default timezone</link>.
</para>
<example id="zend.date.basic.creation.example-1">
<title>Creating the Current Date</title>
<programlisting language="php"><![CDATA[
$date = new Zend_Date();
// Output of the current timestamp
print $date;
]]></programlisting>
</example>
</sect2>
<sect2 id="zend.date.basic.functions">
<title>Zend_Date by Example</title>
<para>
Reviewing basic methods of <classname>Zend_Date</classname> is a good place to start for
those unfamiliar with date objects in other languages or frameworks. A small example
will be provided for each method below.
</para>
<sect3 id="zend.date.simple.functions.get">
<title>Output a Date</title>
<para>
The date in a <classname>Zend_Date</classname> object may be obtained as a localized
integer or string using the <methodname>get()</methodname> method. There are many
available options, which will be explained in later sections.
</para>
<example id="zend.date.simple.functions.get.example-1">
<title>get() - Output a Date</title>
<programlisting language="php"><![CDATA[
$date = new Zend_Date();
// Output of the desired date
print $date->get();
]]></programlisting>
</example>
</sect3>
<sect3 id="zend.date.simple.functions.set">
<title>Setting a Date</title>
<para>
The <methodname>set()</methodname> method alters the date stored in the object, and
returns the final date value as a timestamp (not an object). Again, there are many
options which will be explored in later sections.
</para>
<example id="zend.date.simple.functions.set.example-1">
<title>set() - Set a Date</title>
<programlisting language="php"><![CDATA[
$date = new Zend_Date();
// Setting of a new time
$date->set('13:00:00',Zend_Date::TIMES);
print $date->get(Zend_Date::W3C);
]]></programlisting>
</example>
</sect3>
<sect3 id="zend.date.simple.functions.add">
<title>Adding and Subtracting Dates</title>
<para>
Adding two dates with <methodname>add()</methodname> usually involves adding a real
date in time with an artificial timestramp representing a date part, such as 12
hours, as shown in the example below. Both <methodname>add()</methodname> and
<methodname>sub()</methodname> use the same set of options as
<methodname>set()</methodname>, which will be explained later.
</para>
<example id="zend.date.simple.functions.add.example-1">
<title>add() - Adding Dates</title>
<programlisting language="php"><![CDATA[
$date = new Zend_Date();
// changes $date by adding 12 hours
$date->add('12:00:00', Zend_Date::TIMES);
echo "Date via get() = ", $date->get(Zend_Date::W3C), "\n";
// use magic __toString() method to call Zend_Date's toString()
echo "Date via toString() = ", $date, "\n";
]]></programlisting>
</example>
</sect3>
<sect3 id="zend.date.simple.functions.compare">
<title>Comparison of Dates</title>
<para>
All basic <classname>Zend_Date</classname> methods can operate on entire dates
contained in the objects, or can operate on date parts, such as comparing the
minutes value in a date to an absolute value. For example, the current minutes in
the current time may be compared with a specific number of minutes using
<methodname>compare()</methodname>, as in the example below.
</para>
<example id="zend.date.simple.functions.compare.example-1">
<title>compare() - Compare Dates</title>
<programlisting language="php"><![CDATA[
$date = new Zend_Date();
// Comparation of both times
if ($date->compare(10, Zend_Date::MINUTE) == -1) {
print "This hour is less than 10 minutes old";
} else {
print "This hour is at least 10 minutes old";
}
]]></programlisting>
</example>
<para>
For simple equality comparisons, use <methodname>equals()</methodname>, which
returns a boolean.
</para>
<example id="zend.date.simple.functions.compare.example-2">
<title>equals() - Identify a Date or Date Part</title>
<programlisting language="php"><![CDATA[
$date = new Zend_Date();
// Comparation of the two dates
if ($date->equals(10, Zend_Date::HOUR)) {
print "It's 10 o'clock. Time to get to work.";
} else {
print "It is not 10 o'clock. You can keep sleeping.";
}
]]></programlisting>
</example>
</sect3>
</sect2>
</sect1>
<!--
vim:se ts=4 sw=4 et:
-->
|
