PHP array example description_PHP tutorial
今天突然碰到了php的问题,发现这篇文章,很老的文章了,但很实用,下一篇我将整理更新的php5的数组 PHP4.0中共有超过30个新的数组相关函数。其中很多通用函数允许你检查给定数组中是否存在特定对象、对数组元素计数、增加或删除元素,或对元素排序。 如果你有很大的一个数组,而所要完成的仅是找出一个存在的给定值,你可以使用in_array()以返回true 或 false。如下代码将输出“Not found in this array”——因为你将在$namesArray中寻找一个并不存在的“Alber ”。
$namesArray = array("Joe", "Jane", "Bob", "Mary", "Paul", "Eddie", "John");
$lookingFor = "Albert";
if (in_array($lookingFor, $namesArray)) {
echo "Youve found it!";
} else {
echo "Not found in this array!";
}
?>
如果你改变了$lookingFor的值,将其变为“Mary”,你将得到消息“Youve found it!”——因为“Mary”是$namesArray的一部分。
如果希望对数组元素计数,你可以使用count()函数:
$namesArray = array("Joe", "Jane", "Bob", "Mary", "Paul", "Eddie", "John");
$count = count($namesArray); ?>
$count值将为7。
你可以对任何数组添加元素,无论是在已存在数组的开始或末尾。你也可以使用函数以创建一个包含两个或多个数组元素的新数组。合并时每个数组将按需要的顺序排列。如果你的数组已经有内部的排序,你需要对新的合并数组重排序。
让我们从对已存在数组的末尾增添元素开始,使用函数array_push():
/* 创建原始数组 */
$fruitArray = array("apple", "orange", "banana", "kiwi", "pear");
/* 加入到原始数组中 */
array_push($fruitArray, "grape", "pineapple", "tomato");
/* 通过其键值列出每个元素*/
while (list($key,$value) = each($fruitArray)) {
echo "$key : $value
";
}
?>
这将显示:
0 : apple
1 : orange
2 : banana
3 : kiwi
4 : pear
5 : grape
6 : pineapple
7 : tomato
当你需要对数组开头添加元素时,代码非常类似。不同处只是函数名:array_unshift() 而不是array_push()。
/* 创建原始数组 */
$fruitArray = array("apple", "orange", "banana", "kiwi", "pear");
/* 加入到原始数组中 */
array_unshift($fruitArray, "grape", "pineapple", "tomato");
/* 通过其键值列出每个元素*/
while (list($key,$value) = each($fruitArray)) {
echo "$key : $value
";
}
?>
这将显示:
0 : grape
1 : pineapple
2 : tomato
3 : apple
4 : orange
5 : banana
6 : kiwi
7 : pear
函数array_merge()合并两个或更多的数组。
/* 创建原始数组 */
$fruitArray = array("apple", "orange", "banana", "kiwi", "pear");
/* 创建第二个数组 */
$vegArray = array("carrot", "green beans", "asparagus", "artichoke", "corn");
/* 合并为一个数组 */
$goodfoodArray = array_merge($fruitArray, $vegArray);
/* 通过其键值列出每个元素*/
while (list($key,$value) = each($goodfoodArray)) {
echo "$key : $value
";
}
?>
这将显示:
0 : apple
1 : orange
2 : banana
3 : kiwi
4 : pear
5 : carrot
6 : green beans
7 : asparagus
8 : artichoke
9 : corn
现在已经对数组进行了增加元素和合并,现在来练习删除元素函数。你可以使用函数array_pop()从一数组末尾删除一个元素。如果使用函数 array_shift(),则从一数组开头删除一个元素。而实际上当你从数组删除元素时,此元素对你而言仍然可用——当你从已存在的数组中对元素进行 pop 或 shift时。
使用array_pop()函数从数组末尾删除一个值:
/* 创建一数组*/
$fruitArray = array("apple", "orange", "banana", "kiwi", "pear");
/* 在末尾弹出某值 */
$popped = array_pop($fruitArray);
/* 列出新数组内容,以及弹出的值*/
while (list($key,$value) = each($fruitArray)) {
echo "$key : $value
";
}
echo "
and finally, in $popped: $popped";
?>
这将显示:
0 : apple
1 : orange
2 : banana
3 : kiwi
and finally, in $popped: pear
Next, delete an element from the end of an array: ???????????
下面,从数组末尾删除某值:
/* Create an array*/
$fruitArray = array("apple", "orange", "banana", "kiwi", "pear");
/* Shift a value from the head of the array*/
$shifted = array_shift($fruitArray);
/* List the contents of the new array and the shifted value*/
while (list($key,$value ) = each($fruitArray)) {
echo "$key : $value
";
}
echo "
and finally, in $shifted: $shifted";
?>
This will show:
0 : orange
1 : banana
2 : kiwi
3 : pear
and finally, in $shifted: apple
has Many functions can help you sort array elements. But I will demonstrate basic sorting to help you understand the process:
/* Create original array*/
$fruitArray = array("apple", "orange", "banana", "kiwi", "pear");
/* Sort*/
sort($fruitArray);
/* Reset it to correctly display the array from beginning to end */
/* List each element by its key value*/
while (list($key,$value) = each($fruitArray)) {
echo "$key : $value
";
}
?>
This will display:
0 : apple
1 : banana
2 : kiwi
3 : orange
4 : pear

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