w3school的PHP教程提炼（一）PHP基础
w3school的PHP教程提炼（一）PHP基础
本笔记只提炼php需要注意的部分，关于运算符，简单判断等内容一概不写。
1 字符串
1.1 strlen()函数计算字符串长度
<?
php
echo
strlen
(
"
hello world!
"
);
?>
1.2 strops()函数在字符串内检索字符串或字符
<?
php
echo
strpos
(
"
hello world
"
,
"
world
"
);
?>
2 数组
2.1 数值数组 带有数字ID键的数组
自动分配ID键：
$names
=
array
(
"
a
"
,
"
b
"
,
"
c
"
);
人工分配ID键：
$names
[
0
]
=
"
a
"
;
$names
[
1
]
=
"
b
"
;
$names
[
2
]
=
"
c
"
;
使用ID键：
<?
php
echo
$names
[
0
]
.
"
&
"
.
$names
[
1
]
.
"
&
"
.
$names
[
2
];
?>
2.2 关联数组 数组中的每个ID键关联一个值
将值作为键分配：
$ages
=
array
(
"
a
"
=>
10
,
"
b
"
=>
20
,
"
c
"
=>
30
);
另一种方法：
$ages
[
"
a
"
]
=
"
10
"
;
$ages
[
"
b
"
]
=
"
20
"
;
$ages
[
"
c
"
]
=
"
30
"
;
使用ID键：
<?
php
echo
"
a is
"
.
$ages
[
"
a
"
]
.
"
years old.
"
;
?>
2.3 多维数组 包含一个或多个数组的数组（略）
3 循环
3.1 while
<?
php
$i
=
1
;
while
(
$i
<=
5
){
echo
"
the number is
"
.
$i
.
"
<br />
"
$i
++
;
}
?>
3.2 do...while
<?
php
$i
=
0
;
do
{
$i
++
;
echo
"
the number is
"
.
$i
.
"
<br />
"
;
}
while
(
$i
<
5
);
?>
3.3 for
<?
php
for
(
$i
=
1
;
$i
<=
5
;
$i
++
){
echo
"
hello world!<br />
"
;
}
?>
3.4 foreach
foreach语句用于循环遍历数组，每进行一次循环，当前数组元素的值就会被赋值给value变量（数组指针会逐一地移动）以此类推。
语法
foreach
(
array
as
value){
//
...
}
示例：输出给定数组的值
<?
php
$arr
=
array
(
"
one
"
,
"
two
"
,
"
three
"
);
foreach
(
$arr
as
$value
){
echo
"
value:
"
.
$value
.
"
<br />
"
;
}
?>
4 函数
4.1 传递参数
<?
php
function
writeName(
$firstname
,
$lastname
){
echo
$firstname
.
$lastname
.
"
<br />
"
;
}
echo
"
my name is
"
;
writeName(
"
Gang
"
,
"
Li
"
);
echo
"
my name is
"
writeName(
"
San
"
,
"
Zhang
"
);
?>
4.2 返回值
<?
php
function
add(
$x
,
$y
){
$total
=
$x
+
$y
;
return
$total
;
}
echo
"
1 + 2 =
"
.
add(
1
,
2
);
//
print 1 + 2 = 3
?>
5 表单处理
$_GET变量用于收集来自method="get"的表单的值。
$_POST变量用于收集来自method="post"的表单的值。
5.1 $_GET变量
form.php
<
form
action
="welcome.php"
method
="get"
>
Name:
<
input
type
="text"
name
="name"
/>
Age:
<
input
type
="text"
name
="age"
/>
<
input
type
="submit"
/>
</
form
>
welcome.php
Welcome
<?
php
echo
$_GET
[
"
name
"
];
?>.<
br
/>
You are
<?
php
echo
$_GET
[
"
age
"
];
?>
years old
!
5.2 $_POST变量
与$_GET不同之处在于：
$_POST没有发送信息量限制，而$_GET限制100字符
$_POST不在url处体现表单中的值，而$_GET传递的url可以加入收藏夹
5.3 $_REQUEST变量
$_REQUEST变量可用来取得通过get和post方法发送到表单数据的结果