pythonで素数を取得する事は、さほど難しくないと思うんだが、今回は、phpとの処理時間を比較してみたいと思う。
言語ごとの処理速度は色々なサイトで行っているが、結果はどれも処理内容によって違っているので、あまり参考にならない。
ということは、自分で直接コーディングして比較するしかないでしょう。
他人の一喜一憂に付き合う必要はない。
ソースコード
#coding: UTF-8
def getPrimeNumber(num):
flg = 0
for i in range(2 , num-1):
if num % i == 0:
flg = i
break
if flg == 0 :
return True
else :
return False
prime_numbers = []
for i in range(2,100):
if getPrimeNumber(i) == True :
prime_numbers.append(i)
print prime_numbers
実行
$ # python prime_number.py
[2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97]
解説
PythonのBooleanの扱い
pythonでもboolean変数は使えますが、「True」「False」という風にちゃんとキャメルケースで記述すること。
xcodeのnilも違和感あったんだが、それよりは分かりやすいと思う。
PHPとの速度比較
今回は1から１０００までの素数という条件で、実行した結果をtimeコマンドで得た値を載せておきます。
$ time python prime_number.py
[2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281, 283, 293, 307, 311, 313, 317, 331, 337, 347, 349, 353, 359, 367, 373, 379, 383, 389, 397, 401, 409, 419, 421, 431, 433, 439, 443, 449, 457, 461, 463, 467, 479, 487, 491, 499, 503, 509, 521, 523, 541, 547, 557, 563, 569, 571, 577, 587, 593, 599, 601, 607, 613, 617, 619, 631, 641, 643, 647, 653, 659, 661, 673, 677, 683, 691, 701, 709, 719, 727, 733, 739, 743, 751, 757, 761, 769, 773, 787, 797, 809, 811, 821, 823, 827, 829, 839, 853, 857, 859, 863, 877, 881, 883, 887, 907, 911, 919, 929, 937, 941, 947, 953, 967, 971, 977, 983, 991, 997]
real 0m0.037s
user 0m0.020s
sys 0m0.000s
time php prime_number.php
Array
(
[0] => 2
[1] => 3
[2] => 5
[3] => 7
[4] => 11
[5] => 13
[6] => 17
[7] => 19
[8] => 23
[9] => 29
[10] => 31
[11] => 37
[12] => 41
[13] => 43
[14] => 47
[15] => 53
[16] => 59
[17] => 61
[18] => 67
[19] => 71
[20] => 73
[21] => 79
[22] => 83
[23] => 89
[24] => 97
[25] => 101
[26] => 103
[27] => 107
[28] => 109
[29] => 113
[30] => 127
[31] => 131
[32] => 137
[33] => 139
[34] => 149
[35] => 151
[36] => 157
[37] => 163
[38] => 167
[39] => 173
[40] => 179
[41] => 181
[42] => 191
[43] => 193
[44] => 197
[45] => 199
[46] => 211
[47] => 223
[48] => 227
[49] => 229
[50] => 233
[51] => 239
[52] => 241
[53] => 251
[54] => 257
[55] => 263
[56] => 269
[57] => 271
[58] => 277
[59] => 281
[60] => 283
[61] => 293
[62] => 307
[63] => 311
[64] => 313
[65] => 317
[66] => 331
[67] => 337
[68] => 347
[69] => 349
[70] => 353
[71] => 359
[72] => 367
[73] => 373
[74] => 379
[75] => 383
[76] => 389
[77] => 397
[78] => 401
[79] => 409
[80] => 419
[81] => 421
[82] => 431
[83] => 433
[84] => 439
[85] => 443
[86] => 449
[87] => 457
[88] => 461
[89] => 463
[90] => 467
[91] => 479
[92] => 487
[93] => 491
[94] => 499
[95] => 503
[96] => 509
[97] => 521
[98] => 523
[99] => 541
[100] => 547
[101] => 557
[102] => 563
[103] => 569
[104] => 571
[105] => 577
[106] => 587
[107] => 593
[108] => 599
[109] => 601
[110] => 607
[111] => 613
[112] => 617
[113] => 619
[114] => 631
[115] => 641
[116] => 643
[117] => 647
[118] => 653
[119] => 659
[120] => 661
[121] => 673
[122] => 677
[123] => 683
[124] => 691
[125] => 701
[126] => 709
[127] => 719
[128] => 727
[129] => 733
[130] => 739
[131] => 743
[132] => 751
[133] => 757
[134] => 761
[135] => 769
[136] => 773
[137] => 787
[138] => 797
[139] => 809
[140] => 811
[141] => 821
[142] => 823
[143] => 827
[144] => 829
[145] => 839
[146] => 853
[147] => 857
[148] => 859
[149] => 863
[150] => 877
[151] => 881
[152] => 883
[153] => 887
[154] => 907
[155] => 911
[156] => 919
[157] => 929
[158] => 937
[159] => 941
[160] => 947
[161] => 953
[162] => 967
[163] => 971
[164] => 977
[165] => 983
[166] => 991
[167] => 997
)
real 0m0.042s
user 0m0.000s
sys 0m0.020s
この程度の数字であれば、一瞬で終わるので、比較にならないかもしれないが、若干Pythonの方が早いようだ。
ほぼ同じ内容のプログラムという事を考えれば、処理速度の比較としては、問題ないと思うので、PHPが遅いという一般的な解釈は間違っていないようだ。
リンク
色々なプログラム言語でアルゴリズム学習
