p5js Variables

Variables

• In p5js, variables are used to store and manipulate data.
• There are two types of variables:
  • Primitive variables: store single values, such as numbers, strings, or booleans.
    • Example: let x = 10;
  • Complex variables: store multiple values, such as arrays or objects.
    • Example: let colors = ['red', 'green', 'blue'];
• Variables can be declared using the let, const, or var keywords.
• The let keyword is used to declare a variable that can be reassigned.
• The const keyword is used to declare a constant variable that cannot be reassigned.
• The var keyword is used to declare a variable that can be reassigned, but it is not recommended to use it.

Loops

• Loops are used to repeat a block of code multiple times.
• There are two types of loops:
  • For loops: used to iterate over a sequence of numbers or an array.
    • Example: for (let i = 0; i < 5; i++) { console.log(i); }
  • While loops: used to repeat a block of code as long as a condition is true.
    • Example: let i = 0; while (i < 5) { console.log(i); i++; }
• Loops can be used to:
  • Iterate over an array or an object
  • Perform a task multiple times
  • Create animations or interactive effects

Conditional Statements

• Conditional statements are used to make decisions based on conditions or rules.
• There are three types of conditional statements:
  • If statements: used to execute a block of code if a condition is true.
    • Example: if (x > 5) { console.log('x is greater than 5'); }
  • If-else statements: used to execute a block of code if a condition is true, and another block of code if the condition is false.
    • Example: if (x > 5) { console.log('x is greater than 5'); } else { console.log('x is less than or equal to 5'); }
  • Switch statements: used to execute a block of code based on the value of an expression.
    • Example: switch (color) { case 'red': console.log('The color is red'); break; case 'green': console.log('The color is green'); break; default: console.log('The color is unknown'); }
• Conditional statements can be used to:
  • Make decisions based on user input or data
  • Create interactive effects or animations
  • Validate user input or data

变量

• 在 p5js 中，变量用于存储和操作数据。
• 有两种类型的变量：
  • 基本变量：存储单个值，如数字、字符串或布尔值。例如：let x = 10;
  • 复杂变量：存储多个值，如数组或对象。例如：let colors = ['red', 'green', 'blue'];
• 变量可以使用 let、const 或 var 关键字声明。
• let 关键字用于声明可以重新赋值的变量。
• const 关键字用于声明不能重新赋值的常量变量。
• var 关键字用于声明可以重新赋值的变量，但不建议使用。

循环

• 循环用于重复一个代码块多次。
• 有两种类型的循环：
  • for 循环：用于迭代一个数字序列或数组。例如：for (let i = 0; i < 5; i++) { console.log(i); }
  • while 循环：用于重复一个代码块只要条件为 true。例如：let i = 0; while (i < 5) { console.log(i); i++; }
• 循环可以用于：
  • 迭代数组或对象
  • 执行多次任务
  • 创建动画或交互效果

条件语句

• 条件语句用于根据条件或规则做出决策。
• 有三种类型的条件语句：
  • if 语句：用于在条件为 true 时执行一个代码块。例如：if (x > 5) { console.log('x is greater than 5'); }
  • if-else 语句：用于在条件为 true 时执行一个代码块，并在条件为 false 时执行另一个代码块。例如：if (x > 5) { console.log('x is greater than 5'); } else { console.log('x is less than or equal to 5'); }
  • switch 语句：用于根据表达式的值执行一个代码块。例如：switch (color) { case 'red': console.log('The color is red'); break; case 'green': console.log('The color is green'); break; default: console.log('The color is unknown'); }
• 条件语句可以用于：
  • 根据用户输入或数据做出决策
  • 创建交互效果或动画
  • 验证用户输入或数据