Question

我正在研究QT和c ++。作为测试项目的一部分，我需要从复杂的长字符串中获取子字符串，基本上它是网页的源。如果我的问题看起来非常微不足道，那就是因为我是一个天真的qt程序员，并且对正则表达式的经验较少。

字符串： “url_encoded_fmt_stream_map”：“类型=视频％2Fwebm％3B +编解码器的％3D％22vp8.0％2C + Vorbis的％22 \ u0026quality =介质\ u0026itag = 43 \ u0026url = HTTPS％3A％2F％2Fr2 --- sn-ci5gup-qxaz.googlevideo.com％2Fvideoplayback％3Fmime％3Dvideo％252Fwebm％26key％3Dyt6％26initcwndbps％3D386250％26pcm2cms％3Dyes％26requiressl％3Dyes％26signature％3D05FB41F2F9FF5490841C7B9F40748FC4B8F505A3.0D81AB0745519F179CBF4468D2412C2240DC72F0％26ratebypass％3Dyes％26fexp％3D3300119％252C3300131％ 252C3313268％252C9405961％252C9416126％252C9416891％252C9419451％252C9422342％252C9422596％252C9427790％252C9428398％252C9431012％252C9433096％252C9433380％252C9433855％252C9433946％252C9434332％252C9435526％252C9435667％252C9435876％252C9436270％252C9436607％252C9436834％252C9436872％252C9436973％252C9437066％252C9437553％ 252C9437742％252C9438326％252C9439652％252C9439979％252C9440048％252C9440552％252C9440651％26ms％3Dau％26mt％3D1467900993％26sparams％3Ddur％252Cid％252Cinitcwndbps％252Cip％252Cipbits％252Citag％252Clmt％252Cmime％252Cmm％252Cmn％252Cms％252Cmv％252Cpcm2cms％ 252Cpl％252Cratebypass％252Creq uiressl％252Csource％252Cupn％252Cexpire％26mv％3DM％26ip％3D182.68.203.45％26id％3DO-AMB0Fggb71vKhXSdQqcOPdLeb9v0n2GaibsWg_W5L5b7％26毫米％3D31％26mn％3Dsn-ci5gup-qxaz％26upn％3Dfri9F8GP9uA％26source％3Dyoutube％26itag％3D43％ 26pl％3D20％26lmt％3D1445550849945309％26expire％3D1467922869％26sver％3D3％26ipbits％3D0％26dur％3D0.000，类型=视频％2Fmp4％3B +编解码器的％3D％22avc1.42001E％2C + mp4a.40.2％22 < /strong>\u0026quality=medium\u0026itag=18\u0026url=https%3A%2F%2Fr2---sn-ci5gup-qxaz.googlevideo.com%2Fvideoplayback%3Fmime%3Dvideo%252Fmp4%26key%3Dyt6%26initcwndbps ％3D386250％26pcm2cms％3Dyes％26requiressl％3Dyes％26signature％3D4C90C634F68098572BDCA7D5B7946F8A49A17369.D4AB7172922F499596226BA335BDF0B4519A4AC6％26ratebypass％3Dyes％26fexp％3D3300119％252C3300131％252C3313268％252C9405961％252C9416126％252C9416891％252C9419451％252C9422342％252C9422596％252C9427790％252C9428398％252C9431012％252C9433096％252C9433380 ％252C9433855％252C9433946％252C9434332％252C9435526％252C9435667％252C9435876％252C9436270％252C9436607％252C9436834％252C9436872％252C9436973％25 2C9437066％252C9437553％252C9437742％252C9438326％252C9439652％252C9439979％252C9440048％252C9440552％252C9440651％26ms％3Dau％26mt％3D1467900993％26sparams％3Ddur％252Cid％252Cinitcwndbps％252Cip％252Cipbits％252Citag％252Clmt％252Cmime％252Cmm％252Cmn％252Cms％ 252Cmv％252Cpcm2cms％252Cpl％252Cratebypass％252Crequiressl％252Csource％252Cupn％252Cexpire％26mv％3DM％26ip％3D182.68.203.45％26id％3DO-AMB0Fggb71vKhXSdQqcOPdLeb9v0n2GaibsWg_W5L5b7％26毫米％3D31％26mn％3Dsn-ci5gup-qxaz％26upn％3Dfri9F8GP9uA％ 26source％3Dyoutube％26itag％3D18％26pl％3D20％26lmt％3D1465194153116908％26expire％3D1467922869％26sver％3D3％26ipbits％3D0％26dur％3D207.354，类型=视频％2F3gpp％3B +编解码器的％3D％22mp4v.20.3％ 2C + mp4a.40.2％22 \ u0026quality =小\ u0026itag = 36 \ u0026url =

上面的字符串是我完整字符串和类似模式的重要部分。这个网页源有许多编码的网址，我需要分开。以下是我要分开的内容。

子串：

HTTPS％3A％2F％2Fr2 --- sn-ci5gup-qxaz.googlevideo.com％2Fvideoplayback％3Fmime％3Dvideo％252Fwebm％26key％3Dyt6％26initcwndbps％3D386250％26pcm2cms％3Dyes％26requiressl％3Dyes％26signature％3D05FB41F2F9FF5490841C7B9F40748FC4B8F505A3 .0D81AB0745519F179CBF4468D2412C2240DC72F0％26ratebypass％3Dyes％26fexp％3D3300119％252C3300131％252C3313268％252C9405961％252C9416126％252C9416891％252C9419451％252C9422342％252C9422596％252C9427790％252C9428398％252C9431012％252C9433096％252C9433380％252C9433855％252C9433946％252C9434332％252C9435526％252C9435667％252C9435876％252C9436270 ％252C9436607％252C9436834％252C9436872％252C9436973％252C9437066％252C9437553％252C9437742％252C9438326％252C9439652％252C9439979％252C9440048％252C9440552％252C9440651％26ms％3Dau％26mt％3D1467900993％26sparams％3Ddur％252Cid％252Cinitcwndbps％252Cip％252Cipbits％252Citag％252Clmt ％252Cmime％252Cmm％252Cmn％252Cms％252Cmv％252Cpcm2cms％252Cpl％252Cratebypass％252Crequiressl％252Csource％252Cupn％252Cexpire％26mv％3DM％26ip％3D182.68.203.45％26id％3DO-AMB0Fggb71vKhXSdQqcOPdLeb9v0n2GaibsWg_W5L5b7％26毫米％3D 31％26mn％3Dsn-ci5gup-qxaz％26upn％3Dfri9F8GP9uA％26source％3Dyoutube％26itag％3D43％26pl％3D20％26lmt％3D1445550849945309％26expire％3D1467922869％26sver％3D3％26ipbits％3D0％26dur％3D0.000，类型=视频％2Fmp4％3B +编解码器的％3D％22avc1.42001E％2C + mp4a.40.2％22

请帮助并建议我如何使用QT，C ++，正则表达式来做到这一点。我不想使用任何其他编程语言。谢谢＆amp;问候。

Answer 1

在Qt中使用QString类用于处理字符串。您应该学习QString文档部分：Manipulating String Data和Querying String Data。也许QString类的contains()方法足以解决您的问题。

<强> UPD：

子串操作的简单示例：

#include <QCoreApplication>
#include <QDebug>

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    QString bigString = "BigString BigString SubString BigString";
    QString subString = "SubString";

    bool containsFlag = bigString.contains(subString, Qt::CaseSensitive);
    int index = bigString.indexOf(subString, 0, Qt::CaseSensitive);

    qDebug() << "Length of subString: " << subString.length();
    qDebug() << "SubString contains in bigString: " << containsFlag;
    qDebug() << "SubString index in bigString: " << index;

    return a.exec();
}

如您所见，您可以确定subString中是否包含bigString。当然，您可以在subString中确定bigString的索引。您可以将自己的数据放在bigString和subString。

中

如何使用qt获取复杂的子字符串？

1 个答案: