PHP - Manual: Deque

2024-12-22

The Deque class

(No version information available, might only be in Git)

简介

A Deque (pronounced “deck”) is a sequence of values in a contiguous buffer that grows and shrinks automatically. The name is a common abbreviation of “double-ended queue” and is used internally by Ds\Queue.

Two pointers are used to keep track of a head and a tail. The pointers can “wrap around” the end of the buffer, which avoids the need to move other values around to make room. This makes shift and unshift very fast — something a Ds\Vector can’t compete with.

Accessing a value by index requires a translation between the index and its corresponding position in the buffer: ((head + position) % capacity).

Strengths

Supports array syntax (square brackets).
Uses less overall memory than an array for the same number of values.
Automatically frees allocated memory when its size drops low enough.
get(), set(), push(), pop(), shift(), and unshift() are all O(1).

Weaknesses

Capacity must be a power of 2.
insert() and remove() are O(n).

类摘要

class Ds\Deque implements Ds\Sequence, ArrayAccess {

/* Constants */

const int MIN_CAPACITY = 8;

/* 方法 */

public allocate(int $capacity): void

public apply(callable $callback): void

public capacity(): int

public clear(): void

public contains(mixed ...$values): bool

public copy(): Ds\Deque

public filter(callable $callback = ?): Ds\Deque

public find(mixed $value): mixed

public first(): mixed

public get(int $index): mixed

public insert(int $index, mixed ...$values): void

public isEmpty(): bool

public join(string $glue = ?): string

public last(): mixed

public map(callable $callback): Ds\Deque

public merge(mixed $values): Ds\Deque

public pop(): mixed

public push(mixed ...$values): void

public reduce(callable $callback, mixed $initial = ?): mixed

public remove(int $index): mixed

public reverse(): void

public reversed(): Ds\Deque

public rotate(int $rotations): void

public set(int $index, mixed $value): void

public shift(): mixed

public slice(int $index, int $length = ?): Ds\Deque

public sort(callable $comparator = ?): void

public sorted(callable $comparator = ?): Ds\Deque

public sum(): int|float

public toArray(): array

public unshift(mixed $values = ?): void

}

预定义常量

Ds\Deque::MIN_CAPACITY

更新日志

版本	说明
PECL ds 1.3.0	The class now implements ArrayAccess.

Ds\Deque::allocate — Allocates enough memory for a required capacity
Ds\Deque::apply — Updates all values by applying a callback function to each value
Ds\Deque::capacity — Returns the current capacity
Ds\Deque::clear — Removes all values from the deque
Ds\Deque::__construct — Creates a new instance
Ds\Deque::contains — Determines if the deque contains given values
Ds\Deque::copy — Returns a shallow copy of the deque
Ds\Deque::count — Returns the number of values in the collection
Ds\Deque::filter — Creates a new deque using a callable to determine which values to include
Ds\Deque::find — Attempts to find a value's index
Ds\Deque::first — Returns the first value in the deque
Ds\Deque::get — Returns the value at a given index
Ds\Deque::insert — Inserts values at a given index
Ds\Deque::isEmpty — Returns whether the deque is empty
Ds\Deque::join — Joins all values together as a string
Ds\Deque::jsonSerialize — Returns a representation that can be converted to JSON
Ds\Deque::last — Returns the last value
Ds\Deque::map — Returns the result of applying a callback to each value
Ds\Deque::merge — Returns the result of adding all given values to the deque
Ds\Deque::pop — Removes and returns the last value
Ds\Deque::push — Adds values to the end of the deque
Ds\Deque::reduce — Reduces the deque to a single value using a callback function
Ds\Deque::remove — Removes and returns a value by index
Ds\Deque::reverse — Reverses the deque in-place
Ds\Deque::reversed — Returns a reversed copy
Ds\Deque::rotate — Rotates the deque by a given number of rotations
Ds\Deque::set — Updates a value at a given index
Ds\Deque::shift — Removes and returns the first value
Ds\Deque::slice — Returns a sub-deque of a given range
Ds\Deque::sort — Sorts the deque in-place
Ds\Deque::sorted — Returns a sorted copy
Ds\Deque::sum — Returns the sum of all values in the deque
Ds\Deque::toArray — Converts the deque to an array
Ds\Deque::unshift — Adds values to the front of the deque

add a note

User Contributed Notes

There are no user contributed notes for this page.

官方地址：https://www.php.net/manual/en/class.ds-deque.php

有任何技术问题请点击这里网站运营推广招聘

IT PHP 编程语言 Linux 开发编程科技 Elasticsearch HTML/CSS/XML 网络数据库 JAVA 面试 NoSQL C/C++ Golang Git 算法操作系统正则表达式 Redis 互联网 MySql JavaScript 运维软件国际架构设计 Mac OS TCP/IP Excel Vim Windows Socket Oracle VR MongoDB Python 运营 MemCache 商业硬件电子娱乐设计 nginx 摄影游戏 WordPress HTTP 团建数码电器

php7 安装fileinfo扩展 preg_split — 通过一个正则表达式分隔字符串 php位值,解决 PHP 中 usort 在值相同时改变原始位置的问题 [PHP] inet_pton/inet_ntop IP地址转换函数 [鸟哥]PHP_INT_MIN 和 -9223372036854775808 PHP 8.1 adodb手册 ADORecordSet对象 opcache预加载 Composer的Packagist资源 array_multisort() 多字段排序 PHPMailer设置utf8 PHPMailer字符集CharSet mysql面试题 PHP json解析（json_decode）页面工具 [原创]诡异的php-fpm超时问题 php中几种注释规范纯php实现DES以及TripleDES加密算法 php 修改图片大小 [鸟哥]PHP FFI详解 - 一种全新的PHP扩展方式 PHP5 扩展SOAP 调用 webservice

略微加速

PHP官方手册 - 互联网笔记