Question

当我使用种子设置新的Random时，我第一次调用它时，我总是得到一个非常相似的数字。后来的电话似乎实际上给我一个随机数。

    for(int i=1;i<100;i++){
        System.out.print(Integer.toString(i)+" ");
        Random r = new Random(i);
        System.out.print(r.nextDouble());
    }

1: 0.7308781907032909 2: 0.7311469360199058 3: 0.731057369148862 4: 0.7306094602878371 5: 0.730519863614471 6: 0.7307886238322471 7: 0.7306990420600421 8: 0.7302511331990172 9: 0.7301615514268123 10: 0.7304302967434272 11: 0.7303407149712222 12: 0.7298928061101974 13: 0.7298032243379924 14: 0.7300719696546073 15: 0.7299823878824023 16: 0.7324010808307754 17: 0.7323115139597316 18: 0.7325802592763465 19: 0.7324906626029803 20: 0.7320427537419555 21: 0.7319531868709117 22: 0.7322219172863654 23: 0.7321323355141605 24: 0.7316844415542968 25: 0.7315948597820918 26: 0.7318635901975455 27: 0.7317740084253406 28: 0.7313261144654769 29: 0.7312365177921107 30: 0.7315052631087257 31: 0.7314156962376819 32: 0.7281011855672591 33: 0.7280116037950541 34: 0.7282803491116691 35: 0.7281907524383029 36: 0.7277428584784392 37: 0.7276532767062343 38: 0.7279220220228492 39: 0.727832425349483 40: 0.7273845313896193 41: 0.7272949496174144 42: 0.7275636800328681 43: 0.7274741131618243 44: 0.7270262043007995 45: 0.7269366225285945 46: 0.7272053678452094 47: 0.7271157860730044 48: 0.7295344790213775 49: 0.7294448972491725 50: 0.7297136425657874 51: 0.7296240607935824 52: 0.7291761519325576 53: 0.7290865701603526 54: 0.7293553154769675 55: 0.7292657486059237 56: 0.7288178248437377 57: 0.7287282430715327 58: 0.7289970032893088 59: 0.7289074066159427 60: 0.7284594977549178 61: 0.728369930883874 62: 0.7286386762004889 63: 0.7285490795271228 64: 0.7252345688567 65: 0.725144987084495 66: 0.7254137473022712 67: 0.7253241655300662 68: 0.7248762417678801 69: 0.7247866748968363 70: 0.7250554202134513 71: 0.7249658384412463 72: 0.7245179146790602 73: 0.7244283478080165 74: 0.7246970931246314 75: 0.7246075113524264 76: 0.7241596024914015 77: 0.7240700207191966 78: 0.7243387660358115 79: 0.7242491693624453 80: 0.7266678772119796 81: 0.7265782954397746 82: 0.7268470407563895 83: 0.7267574589841845 84: 0.7263095650243209 85: 0.7262199683509547 86: 0.7264887136675696 87: 0.7263991318953646 88: 0.725951237935501 89: 0.7258616412621348 90: 0.7261303865787497 91: 0.7260408048065448 92: 0.7255929108466811 93: 0.7255033141733149 94: 0.7257720594899298 95: 0.7256824926188861 96: 0.7223679819484633 97: 0.7222784001762583 98: 0.722547130591712 99: 0.7224575488195071

    for(int i=1;i<100;i++){
        System.out.print(Integer.toString(i)+" ");
        Random r = new Random(i);
        r.nextDouble();
        System.out.print(r.nextDouble());
    }

1: 0.41008081149220166 2: 0.9014476240300544 3: 0.07099203475193139 4: 0.9187140138555101 5: 0.08825840967622589 6: 0.5796252073129174 7: 0.7491696031336331 8: 0.5968915822372118 9: 0.7664359929590888 10: 0.2578027905957804 11: 0.42734718641649616 12: 0.2750691655200749 13: 0.44461356134079055 14: 0.9359803887798046 15: 0.10552478460052028 16: 0.527826082540034 17: 0.6973704783607497 18: 0.18873727599744128 19: 0.35828168671931826 20: 0.20600366582289698 21: 0.37554806164361276 22: 0.8669148741814655 23: 0.03645927000218119 24: 0.88418124910576 25: 0.053725659827636885 26: 0.5450924574643284 27: 0.7146368532850442 28: 0.5623588323886229 29: 0.7319032282093387 30: 0.22327004074719148 31: 0.39281443656790715 32: 0.6659570968355509 33: 0.8355014926562667 34: 0.32686830519411947 35: 0.49641270101483514 36: 0.34413468011841397 37: 0.5136790759391296 38: 0.00504590337814359 39: 0.17459029919885938 40: 0.022312278302438093 41: 0.19185667412315388 42: 0.6832234717598454 43: 0.8527678824817223 44: 0.700489861585301 45: 0.8700342574060168 46: 0.36140105504270836 47: 0.5309454508634242 48: 0.953246763704099 49: 0.12279115952481479 50: 0.6141579720626675 51: 0.7837023678833833 52: 0.631424346986962 53: 0.8009687428076777 54: 0.29233554044436927 55: 0.46187995116624625 56: 0.30960193026982497 57: 0.47914632609054075 58: 0.9705131386283935 59: 0.1400575344491093 60: 0.987779513552688 61: 0.15732392427456487 62: 0.6486907219112564 63: 0.8182351177319722 64: 0.09137779290077719 65: 0.26092217382033167 66: 0.7522889863581844 67: 0.9218333821789002 68: 0.7695553612824789 69: 0.9390997720043559 70: 0.43046656964104746 71: 0.6000109654617632 72: 0.44773294456534196 73: 0.6172773403860576 74: 0.10864416782507158 75: 0.2781885487446262 76: 0.12591054274936608 77: 0.2954549236689207 78: 0.7868217511079346 79: 0.9563661469286503 80: 0.37866742996700287 81: 0.5482118406888798 82: 0.039578653226732596 83: 0.20912304904744827 84: 0.05684502815102699 85: 0.22638940907058158 86: 0.7177562365095955 87: 0.8873006323303113 88: 0.73502261143389 89: 0.9045670072546057 90: 0.39593381979245856 91: 0.5654782156131742 92: 0.41320019471675296 93: 0.5827445905374687 94: 0.07411140307532149 95: 0.24365579889603728 96: 0.516798459163681 97: 0.6863428549843967 98: 0.17770968242341068 99: 0.34725406334296527 FINAL SUMMARY

这让我随机数字。这是预期的吗？为什么？我正在跑步：

Java（TM）SE运行时环境（版本1.8.0_101-b13）
Java HotSpot（TM）64位服务器VM（版本25.101-b13，混合模式）

Answer 1

在您的第一个代码中，您在播种非常“接近”的值后打印第一个随机数。

但是在你的第二个循环中，你正在调用nextDouble两次，而你只打印第二个调用的结果！

为什么在设置随机种子后我总是得到相同的随机双倍？

1 个答案: