浅谈php随机不重复数的两种算法-php手册-php.cn

Rumah

php教程

php手册

浅谈php随机不重复数的两种算法

WBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWB

Jun 06, 2016 pm 07:50 PM

phpjamakmemperkenalkanalgoritmarawak

先引入别人的一个秒表计时类（counttime.class.php）： 1.先看第一个例子（大数中取少数）： 1 ? 2 /* 3 @描述: Stopwatch这个类用户获取脚本执行时间 4 @作者: Klesti Hoxha klesti@gmail.com 5 */ 6 7 class Stopwatch { 8 private $start ; 9 private $en

先引入别人的一个秒表计时类（counttime.class.php）：

1.先看第一个例子（大数中取少数）：

<span> 1</span> 
<span> 2</span> <span>/*</span>
<span> 3</span> <span>@描述: Stopwatch这个类用户获取脚本执行时间
</span><span> 4</span> <span>@作者: Klesti Hoxha <klesti>
</klesti></span><span> 5</span> <span>*/</span>
<span> 6</span> 
<span> 7</span> <span>class</span><span> Stopwatch {
</span><span> 8</span> <span>private</span> <span>$start</span><span>;
</span><span> 9</span> <span>private</span> <span>$end</span><span>;
</span><span>10</span> <span>private</span> <span>$markup_start</span> = <span>array</span><span>();
</span><span>11</span> <span>private</span> <span>$markup_end</span> = <span>array</span><span>();
</span><span>12</span> 
<span>13</span> <span>function</span> __construct(<span>$markup</span>=<span>false</span><span>) {
</span><span>14</span> <span>$this</span>->start(<span>$markup</span><span>);
</span><span>15</span> <span>}
</span><span>16</span> 
<span>17</span> <span>public</span> <span>function</span> start(<span>$markup</span>=<span>false</span><span>) {
</span><span>18</span> <span>if</span> (!<span>$markup</span><span>) {
</span><span>19</span> <span>$this</span>->start = <span>$this</span>-><span>getmicrotime();
</span><span>20</span> } <span>else</span><span> {
</span><span>21</span> <span>$this</span>->markup_start[<span>$markup</span>] = <span>$this</span>-><span>getmicrotime();
</span><span>22</span> <span>}
</span><span>23</span> <span>}
</span><span>24</span> 
<span>25</span> <span>public</span> <span>function</span> stop(<span>$markup</span>=<span>false</span><span>) {
</span><span>26</span> <span>if</span> (!<span>$markup</span><span>) {
</span><span>27</span> <span>$this</span>-><span>end</span> = <span>$this</span>-><span>getmicrotime();
</span><span>28</span> } <span>else</span><span> {
</span><span>29</span> <span>$this</span>->markup_end[<span>$markup</span>] = <span>$this</span>-><span>getmicrotime();
</span><span>30</span> <span>}
</span><span>31</span> <span>return</span> <span>$this</span>->getDuration(<span>$markup</span><span>);
</span><span>32</span> <span>}
</span><span>33</span> 
<span>34</span> <span>public</span> <span>function</span> getDuration(<span>$markup</span>=<span>false</span><span>) {
</span><span>35</span>     <span>if</span> (!<span>$markup</span><span>)
</span><span>36</span> <span>     {
</span><span>37</span>         <span>return</span> <span>number_format</span>(<span>$this</span>-><span>end</span>-<span>$this</span>->start,4<span>);
</span><span>38</span>     } <span>else</span><span> {
</span><span>39</span>         <span>return</span> <span>number_format</span>(<span>$this</span>->markup_end[<span>$markup</span>]-<span>$this</span>->markup_start[<span>$markup</span>],4<span>);
</span><span>40</span> <span>    }
</span><span>41</span> <span>}
</span><span>42</span> 
<span>43</span> <span>public</span> <span>function</span> <span>reset</span>(<span>$markup</span><span>) {
</span><span>44</span> <span>if</span> (!<span>$markup</span><span>) {
</span><span>45</span> <span>$this</span>->start = 0<span>;
</span><span>46</span> <span>$this</span>-><span>end</span> = 0<span>;
</span><span>47</span> <span>$this</span>->markup_start = <span>array</span><span>();
</span><span>48</span> <span>$this</span>->markup_end = <span>array</span><span>();
</span><span>49</span> } <span>else</span><span> {
</span><span>50</span> <span>$this</span>->markup_start[<span>$markup</span>] = 0<span>;
</span><span>51</span> <span>$this</span>->markup_end[<span>$markup</span>] = 0<span>;
</span><span>52</span> <span>}
</span><span>53</span> <span>}
</span><span>54</span> 
<span>55</span> <span>private</span> <span>function</span><span> getmicrotime(){
</span><span>56</span> <span>list</span>(<span>$usec</span>, <span>$sec</span>) = <span>explode</span>(" ",<span>microtime</span><span>());
</span><span>57</span> <span>return</span> ((<span>float</span>)<span>$usec</span> + (<span>float</span>)<span>$sec</span><span>);
</span><span>58</span> <span>}
</span><span>59</span> 
<span>60</span> <span>}
</span><span>61</span> ?>

测试的两种方法如下：

<span> 1</span> <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<span> 2</span> <span>php
</span><span> 3</span> <span>require</span> "counttime.class.php";<span>//</span><span>把类文件引用进来，根据你的实际情况来确定路径，这里是在同级目录</span>
<span> 4</span> <span>$s</span> = <span>new</span><span> Stopwatch();
</span><span> 5</span> 
<span> 6</span> <span>$s</span>->start("div1"<span>);
</span><span> 7</span> <span>//</span><span>range 是将1到100 列成一个数组</span>
<span> 8</span> <span>$numbers</span> = <span>range</span> (1,1000000<span>);
</span><span> 9</span> <span>//</span><span>shuffle 将数组顺序随即打乱</span>
<span>10</span> <span>shuffle</span> (<span>$numbers</span><span>);
</span><span>11</span> <span>//</span><span>array_slice 取该数组中的某一段</span>
<span>12</span> <span>$no</span>=30<span>;
</span><span>13</span> <span>$result</span> = <span>array_slice</span>(<span>$numbers</span>,0,<span>$no</span><span>);
</span><span>14</span> <span>for</span> (<span>$i</span>=0;<span>$i</span>$no;<span>$i</span>++<span>){
</span><span>15</span> <span>echo</span> <span>$result</span>[<span>$i</span>]."<br>"<span>;
</span><span>16</span> <span>}
</span><span>17</span> <span>echo</span> "第一个测验方法结束<br><br>"<span>;
</span><span>18</span> <span>$s</span>->stop("div1"<span>);
</span><span>19</span> 
<span>20</span> <span>$s</span>->start("div2"<span>);
</span><span>21</span> <span>function</span> unique_rand(<span>$min</span>, <span>$max</span>, <span>$num</span><span>)
</span><span>22</span> <span>{
</span><span>23</span>         <span>$count</span> = 0<span>;
</span><span>24</span>         <span>$return</span> = <span>array</span><span>();
</span><span>25</span>         <span>while</span> (<span>$count</span> $num<span>) {
</span><span>26</span>             <span>$return</span>[] = <span>mt_rand</span>(<span>$min</span>, <span>$max</span><span>);
</span><span>27</span>             <span>$return</span> = <span>array_flip</span>(<span>array_flip</span>(<span>$return</span><span>));
</span><span>28</span>             <span>$count</span> = <span>count</span>(<span>$return</span><span>);
</span><span>29</span> <span>        }
</span><span>30</span>         <span>shuffle</span>(<span>$return</span><span>);
</span><span>31</span>         <span>return</span> <span>$return</span><span>;
</span><span>32</span> <span>}
</span><span>33</span> 
<span>34</span>     <span>$arr</span> = unique_rand(1, 100000000000, 30<span>);
</span><span>35</span>     <span>$result</span> = ''<span>;
</span><span>36</span>     <span>for</span>(<span>$i</span>=0; <span>$i</span> count(<span>$arr</span>);<span>$i</span>++<span>)
</span><span>37</span> <span>    {
</span><span>38</span>         <span>$result</span> = <span>$arr</span>[<span>$i</span><span>];
</span><span>39</span>         <span>echo</span> <span>$result</span>."<br>"<span>;
</span><span>40</span> <span>    }
</span><span>41</span>     <span>$s</span>->stop("div2"<span>);
</span><span>42</span> 
<span>43</span> 
<span>44</span> <span>//</span><span>输出时间</span>
<span>45</span> <span>echo</span> "div 1 Duration: " . <span>$s</span>->getDuration("div1") . " seconds.<br>"<span>;
</span><span>46</span> <span>echo</span> "div 2 Duration: " . <span>$s</span>->getDuration("div2") . " seconds.<br>"<span>;
</span><span>47</span> ?>

结果为：

<span> 1</span> 413537
<span> 2</span> 198587
<span> 3</span> 60611
<span> 4</span> 599544
<span> 5</span> 946241
<span> 6</span> 462853
<span> 7</span> 570943
<span> 8</span> 980260
<span> 9</span> 717416
<span>10</span> 969324
<span>11</span> 292403
<span>12</span> 614443
<span>13</span> 769469
<span>14</span> 151951
<span>15</span> 167883
<span>16</span> 308727
<span>17</span> 342706
<span>18</span> 955659
<span>19</span> 112311
<span>20</span> 329008
<span>21</span> 182668
<span>22</span> 330600
<span>23</span> 921966
<span>24</span> 993143
<span>25</span> 369227
<span>26</span> 747066
<span>27</span> 793185
<span>28</span> 347872
<span>29</span> 439016
<span>30</span> 428600
<span>31</span> <span>第一个测验方法结束
</span><span>32</span> 
<span>33</span> 649589727
<span>34</span> 450823813
<span>35</span> 324717181
<span>36</span> 44553762
<span>37</span> 375669657
<span>38</span> 37128612
<span>39</span> 25135327
<span>40</span> 468454185
<span>41</span> 73395357
<span>42</span> 753960006
<span>43</span> 214455797
<span>44</span> 5367614
<span>45</span> 1153263961
<span>46</span> 17803441
<span>47</span> 669057198
<span>48</span> 55366324
<span>49</span> 1117343950
<span>50</span> 203530485
<span>51</span> 1160930064
<span>52</span> 326487914
<span>53</span> 565471236
<span>54</span> 7068443
<span>55</span> 846955001
<span>56</span> 832037489
<span>57</span> 1067813034
<span>58</span> 219239595
<span>59</span> 1069795964
<span>60</span> 1049898846
<span>61</span> 926301266
<span>62</span> 197341539
<span>63</span> div 1 Duration: 0.5800 seconds.
<span>64</span> div 2 Duration: 0.0000 seconds.

结论：对于从大量数据中取少量数据，显然第二种比较快。

2.在来看看从大数中取大数：

<span> 1</span> <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<span> 2</span> <span>php
</span><span> 3</span> <span>require</span> "counttime.class.php";<span>//</span><span>把类文件引用进来，根据你的实际情况来确定路径，这里是在同级目录</span>
<span> 4</span> <span>$s</span> = <span>new</span><span> Stopwatch();
</span><span> 5</span> 
<span> 6</span> <span>$s</span>->start("div1"<span>);
</span><span> 7</span> <span>//</span><span>range 是将1到100 列成一个数组</span>
<span> 8</span> <span>$numbers</span> = <span>range</span> (1,1000000<span>);
</span><span> 9</span> <span>//</span><span>shuffle 将数组顺序随即打乱</span>
<span>10</span> <span>shuffle</span> (<span>$numbers</span><span>);
</span><span>11</span> <span>//</span><span>array_slice 取该数组中的某一段</span>
<span>12</span> <span>$no</span>=10000<span>;
</span><span>13</span> <span>$result</span> = <span>array_slice</span>(<span>$numbers</span>,0,<span>$no</span><span>);
</span><span>14</span> <span>for</span> (<span>$i</span>=0;<span>$i</span>$no;<span>$i</span>++<span>){
</span><span>15</span> <span>echo</span> <span>$result</span>[<span>$i</span>]."<br>"<span>;
</span><span>16</span> <span>}
</span><span>17</span> <span>echo</span> "第一个测验方法结束<br><br>"<span>;
</span><span>18</span> <span>$s</span>->stop("div1"<span>);
</span><span>19</span> 
<span>20</span> <span>$s</span>->start("div2"<span>);
</span><span>21</span> <span>function</span> unique_rand(<span>$min</span>, <span>$max</span>, <span>$num</span><span>)
</span><span>22</span> <span>{
</span><span>23</span>         <span>$count</span> = 0<span>;
</span><span>24</span>         <span>$return</span> = <span>array</span><span>();
</span><span>25</span>         <span>while</span> (<span>$count</span> $num<span>) {
</span><span>26</span>             <span>$return</span>[] = <span>mt_rand</span>(<span>$min</span>, <span>$max</span><span>);
</span><span>27</span>             <span>$return</span> = <span>array_flip</span>(<span>array_flip</span>(<span>$return</span><span>));
</span><span>28</span>             <span>$count</span> = <span>count</span>(<span>$return</span><span>);
</span><span>29</span> <span>        }
</span><span>30</span>         <span>shuffle</span>(<span>$return</span><span>);
</span><span>31</span>         <span>return</span> <span>$return</span><span>;
</span><span>32</span> <span>}
</span><span>33</span> 
<span>34</span>     <span>$arr</span> = unique_rand(1, 1000000, 10000<span>);
</span><span>35</span>     <span>$result</span> = ''<span>;
</span><span>36</span>     <span>for</span>(<span>$i</span>=0; <span>$i</span> count(<span>$arr</span>);<span>$i</span>++<span>)
</span><span>37</span> <span>    {
</span><span>38</span>         <span>$result</span> = <span>$arr</span>[<span>$i</span><span>];
</span><span>39</span>         <span>echo</span> <span>$result</span>."<br>"<span>;
</span><span>40</span> <span>    }
</span><span>41</span>     <span>$s</span>->stop("div2"<span>);
</span><span>42</span> 
<span>43</span> 
<span>44</span> <span>//</span><span>输出时间</span>
<span>45</span> <span>echo</span> "div 1 Duration: " . <span>$s</span>->getDuration("div1") . " seconds.<br>"<span>;
</span><span>46</span> <span>echo</span> "div 2 Duration: " . <span>$s</span>->getDuration("div2") . " seconds.<br>"<span>;
</span><span>47</span> ?>

输出结果为：

<span>1</span> <span>前面省略………………
</span><span>2</span> div 1 Duration: 0.6050 seconds.
<span>3</span> div 2 Duration: 17.4260 seconds.

结论：对于第一种方法输出一个数据的时间，跟大数的数字时间差不多。但是第二个时间显然耗费得要离谱。达到了17.5秒。

总结：

1.翻翻法对于选少量数据好用，大量数据就会比较吃力。

Kenyataan

Kandungan artikel ini disumbangkan secara sukarela oleh netizen, dan hak cipta adalah milik pengarang asal. Laman web ini tidak memikul tanggungjawab undang-undang yang sepadan. Jika anda menemui sebarang kandungan yang disyaki plagiarisme atau pelanggaran, sila hubungi admin@php.cn

Alat AI Hot

Undresser.AI Undress

Apl berkuasa AI untuk mencipta foto bogel yang realistik

AI Clothes Remover

Alat AI dalam talian untuk mengeluarkan pakaian daripada foto.

Undress AI Tool

Gambar buka pakaian secara percuma

Clothoff.io

Penyingkiran pakaian AI

AI Hentai Generator

Menjana ai hentai secara percuma.

Tunjukkan Lagi

Artikel Panas

R.E.P.O. Kristal tenaga dijelaskan dan apa yang mereka lakukan (kristal kuning)

3 minggu yang laluBy尊渡假赌尊渡假赌尊渡假赌

R.E.P.O. Tetapan grafik terbaik

3 minggu yang laluBy尊渡假赌尊渡假赌尊渡假赌

Assassin's Creed Shadows: Penyelesaian Riddle Seashell

2 minggu yang laluByDDD

R.E.P.O. Cara Memperbaiki Audio Jika anda tidak dapat mendengar sesiapa

3 minggu yang laluBy尊渡假赌尊渡假赌尊渡假赌

WWE 2K25: Cara Membuka Segala -galanya Di Myrise

4 minggu yang laluBy尊渡假赌尊渡假赌尊渡假赌

Tunjukkan Lagi

Alat panas

MinGW - GNU Minimalis untuk Windows

Projek ini dalam proses untuk dipindahkan ke osdn.net/projects/mingw, anda boleh terus mengikuti kami di sana. MinGW: Port Windows asli bagi GNU Compiler Collection (GCC), perpustakaan import yang boleh diedarkan secara bebas dan fail pengepala untuk membina aplikasi Windows asli termasuk sambungan kepada masa jalan MSVC untuk menyokong fungsi C99. Semua perisian MinGW boleh dijalankan pada platform Windows 64-bit.

SublimeText3 Linux versi baharu

SublimeText3 Linux versi terkini

DVWA

Damn Vulnerable Web App (DVWA) ialah aplikasi web PHP/MySQL yang sangat terdedah. Matlamat utamanya adalah untuk menjadi bantuan bagi profesional keselamatan untuk menguji kemahiran dan alatan mereka dalam persekitaran undang-undang, untuk membantu pembangun web lebih memahami proses mengamankan aplikasi web, dan untuk membantu guru/pelajar mengajar/belajar dalam persekitaran bilik darjah Aplikasi web keselamatan. Matlamat DVWA adalah untuk mempraktikkan beberapa kelemahan web yang paling biasa melalui antara muka yang mudah dan mudah, dengan pelbagai tahap kesukaran. Sila ambil perhatian bahawa perisian ini

Muat turun versi mac editor Atom

Editor sumber terbuka yang paling popular

Pelayar Peperiksaan Selamat

Pelayar Peperiksaan Selamat ialah persekitaran pelayar selamat untuk mengambil peperiksaan dalam talian dengan selamat. Perisian ini menukar mana-mana komputer menjadi stesen kerja yang selamat. Ia mengawal akses kepada mana-mana utiliti dan menghalang pelajar daripada menggunakan sumber yang tidak dibenarkan.

Tunjukkan Lagi

Topik panas

Di manakah pintu masuk log masuk untuk e-mel gmail?

7474

Tutorial CakePHP

1377

Apakah format nama akaun stim

kunci pengaktifan win11 kekal

Sambungan NYT menunjukkan dan jawapan

Tunjukkan Lagi