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Vector

向量是 Move 中存储元素集合的原生方式。它们与其他编程语言中的数组类似，但也有一些差异。在本节中，我们介绍向量类型及其操作。

Vectors are a native way to store collections of elements in Move. They are similar to arrays in other programming languages, but with a few differences. In this section, we introduce the vector type and its operations.

Vector syntax​

向量类型是使用向量关键字后跟尖括号中的元素类型来定义的。元素的类型可以是任何有效的 Move 类型，包括其他向量。 Move 具有向量文字语法，允许您使用向量关键字创建向量，后跟包含元素的方括号（或者空向量不包含元素）。

The vector type is defined using the vector keyword followed by the type of the elements in angle brackets. The type of the elements can be any valid Move type, including other vectors. Move has a vector literal syntax that allows you to create vectors using the vector keyword followed by square brackets containing the elements (or no elements for an empty vector).

{{#include ../../../packages/samples/sources/move-basics/vector.move:literal}}

矢量类型是 Move 中的内置类型，不需要从模块导入。但是，向量运算是在 std::vector 模块中定义的，您需要导入该模块才能使用它们。

The vector type is a built-in type in Move, and does not need to be imported from a module. However, vector operations are defined in the std::vector module, and you need to import the module to use them.

Vector operations​

标准库提供了操作向量的方法。以下是一些最常用的操作：

  • push_back：将一个元素添加到向量的末尾。
  • pop_back：从向量中删除最后一个元素。
  • length：返回向量中元素的数量。
  • is_empty：如果向量为空，则返回 true。
  • remove：删除给定索引处的元素。

The standard library provides methods to manipulate vectors. The following are some of the most commonly used operations:

  • push_back: Adds an element to the end of the vector.
  • pop_back: Removes the last element from the vector.
  • length: Returns the number of elements in the vector.
  • is_empty: Returns true if the vector is empty.
  • remove: Removes an element at a given index.
{{#include ../../../packages/samples/sources/move-basics/vector.move:methods}}

Destroying a Vector of non-droppable types​

不可丢弃类型的向量不能被丢弃。如果定义不具有丢弃能力的类型向量，则不能忽略向量值。但是，如果向量为空，编译器需要显式调用 destroy_empty 函数。

A vector of non-droppable types cannot be discarded. If you define a vector of types without drop ability, the vector value cannot be ignored. However, if the vector is empty, compiler requires an explicit call to destroy_empty function.

{{#include ../../../packages/samples/sources/move-basics/vector.move:no_drop}}

Further reading​

  • Vector in the Move Reference.