Question

我需要在JavaScript中使用正则表达式的帮助。我有以下字符串（它没有换行符）：

var str = 'DetailedLog 18.11.2015 14:41:35.299 Neutral : 0,5704 Happy : 0,6698 Sad : 0,0013 Angry : 0,0040 Surprised : 0,0129 Scared : 0,0007 Disgusted : 0,0048 Valence : 0,6650 Arousal : 0,2297 Gender : Male Age : 20 - 30 Beard : None Moustache : None Glasses : Yes Ethnicity : Caucasian Y - Head Orientation : -1,7628 X - Head Orientation : 2,5652 Z - Head Orientation : -3,0980 Landmarks : 375,4739 - 121,6879 - 383,2627 - 113,6502 - 390,8202 - 110,3507 - 396,1021 - 109,7039 - 404,9615 - 110,9594 - 443,2603 - 108,9765 - 451,9454 - 106,7192 - 457,1207 - 106,8835 - 464,1162 - 109,5496 - 470,9659 - 116,8992 - 387,4940 - 132,0171 - 406,4031 - 130,4482 - 441,6239 - 128,6356 - 460,6862 - 128,1997 - 419,0713 - 161,6479 - 425,3519 - 155,1223 - 431,9862 - 160,6411 - 406,9320 - 190,3831 - 411,4790 - 188,7656 - 423,1751 - 185,6583 - 428,5339 - 185,6882 - 433,7802 - 184,8167 - 445,6192 - 186,3515 - 450,8424 - 187,2787 - 406,0796 - 191,1880 - 411,9287 - 193,5352 - 417,9666 - 193,6567 - 424,0851 - 193,4941 - 428,6678 - 193,5652 - 433,2172 - 192,7540 - 439,3548 - 192,0136 - 445,4181 - 191,1532 - 451,6007 - 187,9486 - 404,5193 - 190,6352 - 412,8277 - 185,4609 - 421,1355 - 181,2883 - 428,3182 - 181,1826 - 435,2024 - 180,2258 - 443,9292 - 183,2533 - 453,1117 - 187,2288 - 405,9689 - 193,2750 - 410,0249 - 199,8118 - 416,0457 - 203,0374 - 423,4839 - 204,1818 - 429,9247 - 204,2175 - 436,3620 - 203,1305 - 443,4268 - 200,9355 - 448,9572 - 197,1335 - 452,0746 - 190,0314 Quality : 0,8137 Mouth : Closed Left Eye : Open Right Eye : Open Left Eyebrow : Lowered Right Eyebrow : Lowered Identity : NO IDENTIFICATION';

我的目标是从这个混乱中构造一个可用的JavaScript对象，包含属性及其值。我试图使用正则表达式，因为据我所知，它们比使用custum for循环解析更快。执行此操作的代码需要很快。

对于属性名称，我尝试使用以下代码构造字符串数组：

str.match(/(\b[A-Z].*?\b)(?=(\s(:|\d)))/g);

这已经过时了：

["DetailedLog", "Neutral", "Happy", "Sad", "Angry", "Surprised", "Scared", 
"Disgusted", "Valence", "Arousal", "Gender", "Male Age", "Beard", "None Moustache",
"None Glasses", "Yes Ethnicity", "Caucasian Y - Head Orientation", "X - Head Orientation",
"Z - Head Orientation", "Landmarks", "Quality", "Mouth", "Closed Left Eye", 
"Open Right Eye", "Open Left Eyebrow", "Lowered Right Eyebrow", "Lowered Identity"]

在这里，我遇到了一个字符串的问题，这些字符串由两个大写单词组成，如＆＃34;男性时代＆＃34;或者＆＃34;打开左眉毛＆＃34;或＆＃34;封闭左眼＆＃34;。我将用于属性值的第一个单词，因此它会妨碍...

我的第一个问题是给出这个输出的正确正则表达式是什么：

["DetailedLog", "Neutral", "Happy", "Sad", "Angry", "Surprised", "Scared", 
"Disgusted", "Valence", "Arousal", "Gender", "Age", "Beard", "Moustache",
"Glasses", "Ethnicity", "Y - Head Orientation", "X - Head Orientation",
"Z - Head Orientation", "Landmarks", "Quality", "Mouth", "Left Eye", 
"Right Eye", "Left Eyebrow", "Right Eyebrow", "Identity"]

感谢您的帮助。

Answer 1

正则表达式

(?:(DetailedLog) ([^ ]+ [^ ]+)|(\b[A-Z][A-Za-z -]+?) : ((?:(?:-?[\d,]+)(?: - -?[\d,]+)*|(?:(?:[A-Z ]+\b|[A-Za-z]+)))))(?:$| )

https://regex101.com/r/lP9pG2/3

可视化

Regular expression visualization

假设

这里的基本想法是因为我们不知道＆＃34; key＆＃34;我们开始尝试定义＆＃34;值＆＃34;更确切地说，当我们知道价值结束时停止捕捉。

DetailedLog将始终跟随由空格分隔的2组字符，这些字符包括空格将被视为值。
＆＃34; key＆＃34;例如Happy值将是以下之一：
- 由-分隔的一个或多个正数或负数或数字。
- 一个大写字母，后跟一个或多个大写或小写字母。
- 所有大写字符和空格的序列。

注意最后一个＆＃34;所有大写字符和空格的序列＆＃34;是专门捕获Identity的最后一部分NO IDENTIFICATION。 Identity的值或任何其他可能只包含字母和空格的值可能会导致问题，如果它们不是全部大写的话。

示例代码

var result = {};
var myregexp = /(?:(DetailedLog) ([^ ]+ [^ ]+)|(\b[A-Z][A-Za-z -]+?) : ((?:(?:-?[\d,]+)(?: - -?[\d,]+)*|(?:(?:[A-Z ]+\b|[A-Za-z]+)))))(?:$| )/g;
var match = myregexp.exec(str);
while (match != null) {
  if (match[1]) {
    result[match[1]] = match[2];
  } else {
    result[match[3]] = match[4];
  }

  match = myregexp.exec(str);
}

这导致result包含以下对象：

{
    "DetailedLog": "18.11.2015 14:41:35.299",
    "Neutral": "0,5704",
    "Happy": "0,6698",
    "Sad": "0,0013",
    "Angry": "0,0040",
    "Surprised": "0,0129",
    "Scared": "0,0007",
    "Disgusted": "0,0048",
    "Valence": "0,6650",
    "Arousal": "0,2297",
    "Gender": "Male",
    "Age": "20 - 30",
    "Beard": "None",
    "Moustache": "None",
    "Glasses": "Yes",
    "Ethnicity": "Caucasian",
    "Y - Head Orientation": "-1,7628",
    "X - Head Orientation": "2,5652",
    "Z - Head Orientation": "-3,0980",
    "Landmarks": "375,4739 - 121,6879 - 383,2627 - 113,6502 - 390,8202 - 110,3507 - 396,1021 - 109,7039 - 404,9615 - 110,9594 - 443,2603 - 108,9765 - 451,9454 - 106,7192 - 457,1207 - 106,8835 - 464,1162 - 109,5496 - 470,9659 - 116,8992 - 387,4940 - 132,0171 - 406,4031 - 130,4482 - 441,6239 - 128,6356 - 460,6862 - 128,1997 - 419,0713 - 161,6479 - 425,3519 - 155,1223 - 431,9862 - 160,6411 - 406,9320 - 190,3831 - 411,4790 - 188,7656 - 423,1751 - 185,6583 - 428,5339 - 185,6882 - 433,7802 - 184,8167 - 445,6192 - 186,3515 - 450,8424 - 187,2787 - 406,0796 - 191,1880 - 411,9287 - 193,5352 - 417,9666 - 193,6567 - 424,0851 - 193,4941 - 428,6678 - 193,5652 - 433,2172 - 192,7540 - 439,3548 - 192,0136 - 445,4181 - 191,1532 - 451,6007 - 187,9486 - 404,5193 - 190,6352 - 412,8277 - 185,4609 - 421,1355 - 181,2883 - 428,3182 - 181,1826 - 435,2024 - 180,2258 - 443,9292 - 183,2533 - 453,1117 - 187,2288 - 405,9689 - 193,2750 - 410,0249 - 199,8118 - 416,0457 - 203,0374 - 423,4839 - 204,1818 - 429,9247 - 204,2175 - 436,3620 - 203,1305 - 443,4268 - 200,9355 - 448,9572 - 197,1335 - 452,0746 - 190,0314",
    "Quality": "0,8137",
    "Mouth": "Closed",
    "Left Eye": "Open",
    "Right Eye": "Open",
    "Left Eyebrow": "Lowered",
    "Right Eyebrow": "Lowered",
    "Identity": "NO IDENTIFICATION"
}

优化

请记住在任何循环或重复的函数调用之外移动正则表达式的声明（在本例中为myregexp），这样正则表达式只会被编译一次。
是的，可能有更快的方法 - 如果您要比较的话，请使用jsperf.com。

以下是一个示例： http://jsperf.com/image-features-log-parsing/5

请记住，此示例每次都会在循环中编译正则表达式。

Answer 2

我没有足够的声誉来发表评论，因此我将提供部分解决方案。使用正则表达式：/(\b[A-Za-z -]+?) : (.+? )/g，然后仅使用Capture Group 1.结果如下所示：https://regex101.com/r/qJ7jU7/1

唯一的缺点是没有捕获“详细日志”。

根据我的经验，并非所有数据都适合一次性使用Regex，有时您需要将其分解为多个部分。

Answer 3

我认为字符串中的空格有太多用法来使用简单的正则表达式。即使剥离关键字也会导致以下混乱，分成几个步骤以使其更清晰：

str.replace(/([0-9])( - )([0-9])/g,"$1-$3") // get rid of spaces between landmarks hyphen
    .replace(/\: [^ ]+/g,",") // get rid of values
    .replace(/(DetailedLog)([0-9.: ]+)/,"$1, ") // get rid of date
    .replace(/(Identity)(.*)/,"$1") // get rid of value of "identity"

您提出了一个简单的解析器，但如果您事先不知道关键字，则无法使用。如果你事先知道它们：只需构建那个简单的解析器并使用关键字作为分隔符。我相信它会比任何高度复杂的正则表达式更快。您可以使用JISON来避免一些麻烦。

啊，我太晚了。试。

尽管如此，这是一个非常简单，未经优化的基准测试解析器：

// That's how I made the keys-array, not actively used here
str.replace(/([0-9])( - )([0-9])/g,"$1-$3")
     .replace(/\: [^ ]+/g,",")
       .replace(/(DetailedLog)([0-9.: ]+)/,"$1, ")
          .replace(/(Identity)(.*)/,"$1")
            .replace(/([^,]+)/g,"\"$1\"" )
             .replace(/\" /g,"\"")
              .replace(/ \"/g,"\"");

var keys = ["DetailedLog", "Neutral" , "Happy" , "Sad" , "Angry" , "Surprised" ,
            "Scared" , "Disgusted" , "Valence" , "Arousal" , "Gender" , "Age" , "Beard" ,
            "Moustache" , "Glasses" , "Ethnicity" , "Y - Head Orientation" ,
            "X - Head Orientation" , "Z - Head Orientation" ,
            "Landmarks" , "Quality" , "Mouth" , "Left Eye" ,
            "Right Eye" , "Left Eyebrow" , "Right Eyebrow" , "Identity"];

var db = {};
var value;
for(var k = 0;k < keys.length - 1;k++){
  var regex = new RegExp("("+keys[k] + "[ :]+)([^:]+)(" + keys[k+1] + ")");
  value = str.match(regex);
  if(value){
    db[keys[k]] = value[2].trim();    
  }
}
// last one
db[keys[keys.length -1]] = value[2].trim();
// take a look
JSON.stringify(db)

对于几百行左右，它应该足够快，特别是如果你稍微优化一下（例如，预先计算正则表达式，它在循环中执行它有点愚蠢）但是在至少你有一个可以比较的基准，因为我不认为你可以在没有一点努力的情况下慢慢做。

JavaScript使用正则表达式解析日志条目（没有明显的分隔符）

3 个答案:

正则表达式

可视化

假设

示例代码

优化