5 basic concepts that PHP beginners must know

With the continuous development of Internet technology, PHP, as a Web programming language, is becoming more and more popular. PHP is widely used and can be developed using PHP from simple static websites to large e-commerce websites.

Whether you are a novice who is just starting to learn PHP or a developer who already has some experience, it is very necessary to master some basic concepts. In this article, I will introduce 5 basic concepts that PHP beginners must know.

1. Variables

PHP variables are containers used to store data. In PHP, the naming rules for variables follow camel case naming, that is, the first letter of the first word is lowercase, and the first letter of each subsequent word is uppercase. PHP variables are dynamic, that is to say, variables can store various types of data, such as numbers, strings, arrays, etc. When we assign a value to a variable, the variable automatically changes based on the type of value stored.

Example:

$x = 10; // Store an integer
$y = "Hello World!"; // Store a string
$z = array ("apple","banana","orange"); // Store an array

2. Array

Array is one of the most commonly used data types in PHP. It is a container that can store multiple values. Arrays can store different types of data, such as strings, numbers, objects, etc. PHP has three types of arrays: numerically indexed arrays, associative arrays, and multidimensional arrays.

Example:

//Number index array
$numbers = array(1, 2, 3, 4, 5);

//Associative array
$person = array(

"name" => "张三",
"age" => 20,
"email" => "zhangsan@example.com"

);

//Multidimensional array
$students = array(

array("name" => "张三", "age" => 20, "major" => "计算机科学"),
array("name" => "李四", "age" => 21, "major" => "软件工程"),
array("name" => "王五", "age" => 22, "major" => "网络工程")

);

3. Function

A function is an encapsulated program in PHP that can be called when needed. Functions can accept parameters and return values. The use of functions can improve code reusability and maintainability.

Example:

function add($a, $b) {

return $a + $b;

}

echo add(2, 3); // Output: 5

4. Loop

In programming, loop is a very important concept. A loop can repeatedly execute a specific block of code under certain conditions, which is usually a Boolean expression. PHP provides various types of loop structures, including for, while, do-while loops, etc.

Example:

// for loop
for ($i=0; $i<10; $i) {

echo $i;

}

// while loop
$i = 0;
while ($i < 10) {

echo $i;
$i++;

}

5. Conditional statement

Conditional statement is a structure that executes specific code based on certain conditions. Common conditional statements include if, else, elseif statements. By using conditional statements, we can execute different code logic based on different conditions.

Example:

$num = 10;

if ($num > 5) {

echo "这个数大于5";

} elseif ($num == 5) {

echo "这个数等于5";

} else {

echo "这个数小于5";

}

Summary

PHP is a very powerful Web programming language, and it is also very easy to learn. language. In this article, we introduce 5 basic concepts that PHP beginners must know, including variables, arrays, functions, loops, and conditional statements. Of course, this is just the tip of the iceberg of basic PHP knowledge. If you want to truly master PHP programming, you still need continuous learning and practice.

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