使用Regex从Javascript中的字符串中提取多个日期

Question

我是regex的新手，并且看了一遍，虽然我找不到一个有效的正则表达式。字符串中没有空格，日期可以被任何随机文本，非日期字符包围。

示例字符串和预期响应：

EX 1：

From2017-01-01to2017-12-31_custom_EquityPurchaseAgreementMember_custom_FirstPaymentMember_currency_CNY  
var res = ['2017-01-01', '2017-12-31']

EX 2：

From2016-01-01to2016-12-31  
var res = ['2016-01-01', '2016-12-31']

EX 3：

From2017-01-01to2017-12-31_custom_EquityPurchaseAgreementMember_custom_FirstPaymentMember  
var res = ['2017-01-01', '2017-12-31']

EX 4：

AsOf2017-12-31  
var res = ['2017-12-31']

我试过这个正则表达式（等等），但没有用： /\b\d{4}-\d{2}-\d{2}\b/g

我正在使用此工具进行测试： http://rubular.com/r/bce4IHyCjW

Answer 1

您与日期不匹配，因为单词边界\b不匹配，例如m2

尝试不带边界\b

\d{4}\-\d{2}\-\d{2}

const strings = [
  "From2017-01-01to2017-12-31_custom_EquityPurchaseAgreementMember_custom_FirstPaymentMember_currency_CNY",
  "From2016-01-01to2016-12-31",
  "From2017-01-01to2017-12-31_custom_EquityPurchaseAgreementMember_custom_FirstPaymentMe",
  "AsOf2017-12-31"
];
let pattern = /\d{4}\-\d{2}\-\d{2}/g;
strings.forEach((s) => {
  console.log(s.match(pattern));
});

Answer 2

删除字边界\b

var regex =  /\d{4}-\d{2}-\d{2}/g

<强>演示

var str1 = "2017-01-01to2017-12-31_custom_EquityPurchaseAgreementMember_custom_FirstPaymentMember_currency_CNY";
var str2 = "From2016-01-01to2016-12-31";
var str3 = "From2017-01-01to2017-12-31_custom_EquityPurchaseAgreementMember_custom_FirstPaymentMember";
var str4 = "AsOf2017-12-31";

var regex =  /\d{4}-\d{2}-\d{2}/g

console.log( str1.match(regex) );
console.log( str2.match(regex) );
console.log( str3.match(regex) );
console.log( str4.match(regex) );

Answer 3

您可以使用

/(?:^|\D)(\d{4}-\d{2}-\d{2})(?!\d)/g

提取组1.请参阅regex demo。

此处，(?:^|\D)匹配字符串的开头（^）或（|）除数字（\D）以外的任何字符。如果当前位置右侧有一个数字，则(?!\d)是一个负向前瞻，但未达到匹配。

JS Demo：

＆＃13;

＆＃13;

var strs = ["From2017-01-01to2017-12-31_custom_EquityPurchaseAgreementMember_custom_FirstPaymentMember_currency_CNY","From2016-01-01to2016-12-31", "From2017-01-01to2017-12-31_custom_EquityPurchaseAgreementMember_custom_FirstPaymentMember", "AsOf2017-12-31" ];
var rx = /(?:^|\D)(\d{4}-\d{2}-\d{2})(?!\d)/g;
for (var s of strs) {
  console.log(s);
  var res=[], m;
  while (m=rx.exec(s)) {
     res.push(m[1]);
  }
  console.log(res);
}

＆＃13;

＆＃13;

＆＃13;

浏览器支持ECMA 2018标准（支持lookbehinds），

/(?<!\d)\d{4}-\d{2}-\d{2}(?!\d)/g

见another regex demo。如果当前位置的左侧有一个数字，则(?<!\d)是一个负面的后视，但是匹配失败。

JS Demo：

＆＃13;

＆＃13;

var strs = ["From2017-01-01to2017-12-31_custom_EquityPurchaseAgreementMember_custom_FirstPaymentMember_currency_CNY","From2016-01-01to2016-12-31", "From2017-01-01to2017-12-31_custom_EquityPurchaseAgreementMember_custom_FirstPaymentMember", "AsOf2017-12-31" ];
var rx = /(?<!\d)\d{4}-\d{2}-\d{2}(?!\d)/g;
for (var s of strs) {
  console.log(s, "=>", s.match(rx));
}

＆＃13;

＆＃13;

＆＃13;

Answer 4

日期值可以是1-1-2015或01-25-2015因此，为了使您的正则表达式更加通用，您应该使用此正则表达式

var regex = /([0-9]+-[0-9]+-[0-9]+)/g

您可以使用此网站测试您的正则表达式，它非常棒，并且可以为某些语言生成代码regex101