php常用的数组函数及案例，php，mysql当前时间函数

PHP是一门处理数据的流行语言，其中最基本的数据类型之一是数组。它们允许我们保存大量相关数据，而无需在代码中显式引用每个数据项。所以，PHP提供了许多内置数组函数，使我们更轻松地处理数组。在本文中，我们将讨论常用的PHP数组函数和相关案例。

一、常用的PHP数组函数

1. array_push()：将一个或多个元素添加到数组末尾

示例：

```php

$fruits = array("apple", "banana");

array_push($fruits, "orange", "kiwi");

print_r($fruits); // Output: Array ( [0] => apple [1] => banana [2] => orange [3] => kiwi )

```

2. array_pop()：删除并返回数组的最后一个元素

示例：

```php

$fruits = array("apple", "banana", "orange", "kiwi");

$last_fruit = array_pop($fruits);

print_r($fruits); // Output: Array ( [0] => apple [1] => banana [2] => orange )

echo $last_fruit; // Output: kiwi

```

3. array_shift()：删除并返回数组的第一个元素

示例：

```php

$fruits = array("apple", "banana", "orange", "kiwi");

$first_fruit = array_shift($fruits);

print_r($fruits); // Output: Array ( [0] => banana [1] => orange [2] => kiwi )

echo $first_fruit; // Output: apple

```

4. array_unshift()：将一个或多个元素添加到数组的开头

示例：

```php

$fruits = array("apple", "banana", "orange", "kiwi");

array_unshift($fruits, "grape", "pear");

print_r($fruits); // Output: Array ( [0] => grape [1] => pear [2] => apple [3] => banana [4] => orange [5] => kiwi )

```

5. array_slice()：截取数组的一部分

示例：

```php

$fruits = array("apple", "banana", "orange", "kiwi");

$selected_fruits = array_slice($fruits, 1, 2);

print_r($selected_fruits); // Output: Array ( [0] => banana [1] => orange )

```

6. array_merge()：将一个或多个数组合并到一个数组中

示例：

```php

$fruits1 = array("apple", "banana");

$fruits2 = array("orange", "kiwi");

$all_fruits = array_merge($fruits1, $fruits2);

print_r($all_fruits); // Output: Array ( [0] => apple [1] => banana [2] => orange [3] => kiwi )

```

7. in_array()：检查数组中是否存在某个元素

示例：

```php

$fruits = array("apple", "banana", "orange", "kiwi");

if (in_array("banana", $fruits)){

echo "Yes, banana exists in the fruits array.";

} else {

echo "No, banana does not exist in the fruits array.";

} // Output: Yes, banana exists in the fruits array.

```

8. array_key_exists()：检查数组中是否存在某个键

示例：

```php

$person = array("name" => "John", "age" => 25);

if (array_key_exists("name", $person)){

echo "Yes, name exists in the person array.";

} else {

echo "No, name does not exist in the person array.";

} // Output: Yes, name exists in the person array.

```

9. array_search()：根据值搜索数组，并返回相应的键

示例：

```php

$fruits = array("apple", "banana", "orange", "kiwi");

$found_key = array_search("orange", $fruits);

echo "The key for orange is " . $found_key; // Output: The key for orange is 2

```

10. array_unique()：删除数组中的重复项

示例：

```php

$fruits = array("apple", "banana", "orange", "banana", "kiwi");

$unique_fruits = array_unique($fruits);

print_r($unique_fruits); // Output: Array ( [0] => apple [1] => banana [2] => orange [4] => kiwi )

```

二、案例

下面是一个教学机构的学生信息数组，我们可以使用一些数组函数来处理、获取和展示这些信息：

```php

$students = array(

array("name" => "Alice", "age" => 19, "major" => "Mathematics"),

array("name" => "Bob", "age" => 20, "major" => "Computer Science"),

array("name" => "Charlie", "age" => 21, "major" => "English")

);

```

1. 使用 foreach 循环遍历数组，展示学生的姓名和专业：

```php

foreach ($students as $student) {

echo $student["name"] . " is studying " . $student["major"] . "
";

}

// Output:

// Alice is studying Mathematics

// Bob is studying Computer Science

// Charlie is studying English

```

2. 使用 count() 函数获取数组中的学生人数：

```php

$student_count = count($students);

echo "The number of students is " . $student_count . "
";

// Output: The number of students is 3

```

3. 使用 array_column() 函数获取学生的名字：

```php

$names = array_column($students, "name");

print_r($names);

// Output: Array ( [0] => Alice [1] => Bob [2] => Charlie )

```

4. 使用 array_filter() 函数获取所有年龄大于二十岁的学生信息：

```php

$filtered_students = array_filter($students, function($student){

return $student["age"] > 20;

});

print_r($filtered_students);

// Output: Array ( [1] => Array ( [name] => Bob [age] => 20 [major] => Computer Science ) [2] => Array ( [name] => Charlie [age] => 21 [major] => English ) )

```

5. 使用 usort() 函数按学生年龄从小到大排序：

```php

usort($students, function($a, $b){

return $a["age"] > $b["age"];

});

print_r($students);

// Output: Array ( [0] => Array ( [name] => Alice [age] => 19 [major] => Mathematics ) [1] => Array ( [name] => Bob [age] => 20 [major] => Computer Science ) [2] => Array ( [name] => Charlie [age] => 21 [major] => English ) )

```

三、PHP MySQL当前时间函数

当使用MySQL进行数据库开发时，我们可能需要在PHP代码中使用MySQL中的时间函数，例如获取当前时间。下面是一些常用的PHP MySQL时间函数：

1. NOW()：返回当前日期和时间

示例：

```php

$query = "INSERT INTO my_table (name, created_at) VALUES ('Alice', NOW())";

```

2. DATE()：返回日期部分

示例：

```php

$query = "SELECT * FROM my_table WHERE DATE(created_at) = '2021-10-20'";

```

3. TIME()：返回时间部分

示例：

```php

$query = "SELECT * FROM my_table WHERE TIME(created_at) BETWEEN '09:00:00' AND '12:00:00'";

```

4. YEAR()：返回年份

示例：

```php

$query = "SELECT * FROM my_table WHERE YEAR(created_at) = 2021";

```

5. MONTH()：返回月份

示例：

```php

$query = "SELECT * FROM my_table WHERE MONTH(created_at) = 10";

```

6. DAY()：返回一年中的天数

示例：

```php

$query = "SELECT * FROM my_table WHERE DAY(created_at) = 20";

```

7. WEEKDAY()：返回一周中的工作日，0表示星期一，6表示星期日

示例：

```php

$query = "SELECT * FROM my_table WHERE WEEKDAY(created_at) = 3";

```

8. HOUR()：返回小时数

示例：

```php

$query = "SELECT * FROM my_table WHERE HOUR(created_at) BETWEEN 9 AND 12";

```

9. MINUTE()：返回分钟数

示例：

```php

$query = "SELECT * FROM my_table WHERE MINUTE(created_at) BETWEEN 30 AND 59";

```

10. SECOND()：返回秒数

示例：

```php

$query = "SELECT * FROM my_table WHERE SECOND(created_at) > 30";

```

本文介绍了PHP中一些常用的数组函数及其案例，以及MySQL中的一些时间函数。这些函数可以极大地简化我们的开发过程，并且可以使我们更高效地处理和获取数据。 如果你喜欢我们三七知识分享网站的文章， 欢迎您分享或收藏知识分享网站文章 欢迎您到我们的网站逛逛喔！https://www.ynyuzhu.com/