从字符串中提取日期 [英] Extracting a date from string
问题描述
我正在尝试从字符串中创建一个日期提取器，以捕捉所有YouTube视频的音乐会。许多视频标题格式如下：
I'm trying to create a date extractor from a string to be a catch all on YouTube videos for concerts. Many video titles are formatted as such:
PHISH Reba Comcast Center Hartford CT. 6/18/2010
Phish - It's Ice - November 30, 1991
PHISH - 11.30.91 I didn't know
Phish/Worcester,MA 12-31-91 Llama
Phish: Tube / Runaway Jim [HD] 2011-01-01 - New York, NY
Phish - Stash (Live) 12.29.93
这些只是其中的几个例子。基本上，日期可以是： MM-DD-YYYY 到 MM-DD-YY 到 YY-MM-DD 等等。每个MM和DD可以是1或两个字符。每个YYYY可以是2或4个字符。 - 角色因期间，短划线到斜杠而异，可以通过简单的 /.?/ 在正则表达式中。
Those are just a few of the examples. Basically dates can be anything from: MM-DD-YYYY to MM-DD-YY to YY-MM-DD etc. Each MM and DD can be 1 or two characters. Each YYYY can be 2 or 4 characters. The - character varies from a period, to a dash, to a slash and can be fixed by a simple /.?/ in Regex.
我开始通过删除空格，然后在字符串上运行这个简单的正则表达式：
I began by stripping the whitespace and then running this simple Regex on the strings:
str.replace((new RegExp(' ', 'g')), '').match(/(([0-9]{1,4}).?([0-9]{1,2}).?([0-9]{1,4}))/)
// to highlight the regex:
// (([0-9]{1,4}).?([0-9]{1,2}).?([0-9]{1,4}))
这似乎工作得很好，但是我也必须包括这个数字是年份，即月，日等的逻辑。同时检测到错误的肯定。
This seems to work pretty well, but I also have to include the logic around which number is the year, which is the month, day, etc. along with detecting false positives.
此外，虽然我不希望能够检测到11月2日为11/2，这将是很酷:)
Also, while I don't expect to be able to detect "November 2" as 11/2, that would be cool :)
有人可以推我一点还是建议任何解决方案？我不想使用图书馆...我宁愿为此写一些特定的代码，因为它不是非常复杂的。感谢
Can anyone push me forward a bit or suggest any solutions? I don't want to use a library... I'd rather write specific code to this as it's not terribly complicated. Thanks
这是一个测试环境（打开您的控制台查看结果），以便您轻松播放数据。 http://jsfiddle.net/ZNLxW/4/
Here's a testing environment (open your console to see results) so you can play with the data easily. http://jsfiddle.net/ZNLxW/4/
推荐答案
这是我的尝试（使用 jsfiddle ）
Here is my attempt (with jsfiddle)
function formatDate(date) {
function lz(value,w) {
value = value.toString();
return "0000".slice(4-w + value.length) + value;
}
return [
lz(date.getFullYear(),4),
lz(date.getMonth()+1,2),
lz(date.getDate(),2)
].join('-');
}
//RegExp with support for short (XdYdZ) and long (month_in_text day, year)
var reDate = new RegExp([
'(?:', // Short format
'\\b',
'(\\d{4}|\\d{1,2})', // field.short_value_1
'\\s*([./-])\\s*', // field.short_del_1
'(\\d{1,2})', // field.short_value_2
'\\s*([./-])\\s*', // field.short_del 2
'(\\d{4}|\\d{1,2})', // field.short_value_3
'\\b',
')|(?:', // Long format
'\\b',
'(', // field.long_month
'jan(?:uary)?|',
'feb(?:ruary)?|',
'mar(?:ch)?|',
'apr(?:il)?|',
'may|',
'jun(?:e)?|',
'jul(?:y)?|',
'aug(?:ust)?|',
'sep(?:tember)?|',
'oct(?:ober)?|',
'nov(?:ember)?|',
'dec(?:ember)?',
')',
'\\s+', // required space
'(\\d{1,2})\\b', // field.long_date
'\\s*', // optional space
',?', // optional delimiter
'\\s*', // optinal space
'(\\d{4}|\\d{2})\\b', // field.long_year
')'
].join(''),'i');
//Month names, must be 3 chars lower case.
//Used to convert month name to number.
var monthNames = [
'jan', 'feb', 'mar', 'apr', 'may', 'jun',
'jul','aug', 'sep', 'oct', 'nov', 'dev'
];
var extractDateFromString = function(str) {
var m = str.match(reDate);
var date;
if (m) {
var idx=-1;
//Convert array form regexp result to named variables.
//Makes it so much easier to change the regexp wihout
//changing the rest of the code.
var field = {
all : m[++idx],
short_value_1 : m[++idx],
short_del_1 : m[++idx],
short_value_2 : m[++idx],
short_del_2 : m[++idx],
short_value_3 : m[++idx],
long_month : m[++idx],
long_date : m[++idx],
long_year : m[++idx]
}
//If field.long_month is set it is a date formated with named month
if (field.long_month) {
var month = monthNames.indexOf(
field.long_month.slice(0,3).toLowerCase()
);
// TODO: Add test for sane year
// TODO: Add test for sane month
// TODO: Add test for sane date
date = new Date(field.long_year,month,field.long_date);
} else {
// Short format: value_1 del_1 value_2 del_2 value_3
var year, month, day;
if (field.short_del_1 != field.short_del_2) {
if (
field.short_del_1 === '/' &&
field.short_del_2 === '-'
) {
// DD/MM-YYYY
year = field.short_value_3;
month = field.short_value_2;
day = field.short_value_1;
console.log('DMY',field.all,+year,+month,+day);
} else {
// TODO: Add other formats here.
// If delimiters don't match it isn't a sane date.
console.log('different delimiters');
}
} else {
// assmume YMD if
// (delimiter = '-' and value_3 < 31)
// or (value_1 > 31)
if (
(field.short_del_1 == '-' || field.short_value_1 > 31)
&& (field.short_value_3 < 32)
) {
// YMD
year = field.short_value_1;
month = field.short_value_2;
day = field.short_value_3;
console.log('YMD',field.all,+year,+month,+day);
} else {
// MDY
year = field.short_value_3;
month = field.short_value_1;
day = field.short_value_2;
console.log('MDY',field.all,+year,+month,+day);
}
}
if (year !== undefined) {
year = +year; //convert to number
//Handle years without a century
//year 00-49 = 2000-2049, 50-99 = 1950-1999
if ( year < 100) {
year += year < 50 ? 2000:1900;
}
date = new Date(year,+month-1,+day);
}
}
}
var div = document.createElement('div');
div.className = date ? 'pass' : 'fail';
div.appendChild(document.createTextNode(date?formatDate(date):'NaD'));
div.appendChild(document.createTextNode(' ' + str));
document.body.appendChild(div);
}
for (var i = 0; i < dates.length; i++) {
extractDateFromString(dates[i].name)
}
更新：调整长格式的正则表达式（添加\b）
Updated: Tweaked the regexp for long format (added \b)
更新：再次调整regexp。没有更多的3位数字段。 （1,2或4）
Updated: Tweaked the regexp again. No more 3 digit fields. (either 1, 2 or 4)
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