部分字符串匹配-动态字符串

Question

对于某些动态字符串，如：

05,2021

• covid-19测试状态，04,2021

• covid-19测试状态，01,2021

• ....

• covid-19测试状态，01,2021

• ....

• covid-19测试状态，直至{日期}

其他如：

，

• ，杰克和琼斯是朋友，

，

• ，杰克和JC是朋友，

，

• ，杰克和伊朗尼是
• ，{朋友名字}}是朋友

。

我想匹配传入的字符串，例如：

covid-19 testing status upto may 01,2021

使用

covid-19 testing status upto {{date}}

如果有匹配，我想提取date的值。

类似地，对于传入的字符串，如

Jack and JC are friends

我想和

Jack and {{friend-name}} are friends

提取JC或者朋友的名字。我怎么能这么做？

我正在尝试创建一个设置，这样的动态字符串可以合并成一个。可能有数以千计的传入字符串，我想要与现有的模式相匹配。

INCOMING_STRINGS -------EXISTING-PATTERNS-----> 
   [
    covid-19 testing status upto {{date}}, 
    Jack and {{friend-name}} are friends, 
    ....
   ] ---> FIND THE PATTERN AND EXTRACT THE DYNAMIC VALUE

编辑

不能保证该模式始终存在于传入字符串中。

Answer 1

第二个示例很容易使用regex。如果将捕获组用于“朋友名”部分，则可以轻松提取：

​

const re = /Jack and ([a-zA-Z]+) are friends/
const inputs = ["Jack and Jones are friends",
"Jack and JC are friends",
"Jack and Irani are friends",
"Bob and John are friends"] // last one wont match

for(let i=0;i<inputs.length;i++){
  const match = inputs[i].match(re);
  if(match)
    console.log("friend=",match[1]);
  else
    console.log("No match for the string:", inputs[i])
}

​

第一个例子有点麻烦，但仅仅是因为正则表达式更难编写。假设格式总是“短月名2位日逗号4位数年”，它是可行的。

​

const re = /covid-19 testing status upto ((jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec) (0?[1-9]|[12][0-9]|3[01]),\d{4})/
const inputs = ["covid-19 testing status upto may 05,2021",
"covid-19 testing status upto may 04,2021",
"covid-19 testing status upto may 01,2021",
"covid-19 testing status upto 01/01/2020"] // wrong date format

for(let i=0;i<inputs.length;i++){
  const match = inputs[i].match(re);
  if(match)
    console.log("date=",match[1]);
  else
    console.log("No match for the string:", inputs[i])
}

​

Answer 2

在我看来，你的实际输入和输出应该是什么，这是相当不清楚的。这是一个猜测的尝试。输入，比如

[{
  sample: 'covid-19 testing status upto may 05,2021',
  extract: 'may 05,2021',
  propName: 'date'
}, {
  sample: 'Jack and Jones are friends',
  extract: 'Jones',
  propName: 'friend-name'
}]

我们生成一个可以像这样使用的函数：

mySubs ('Jack and William are friends')
//=> {"friend-name": "William"}

或

(mySubs ('covid-19 testing status upto apr 30,2021')
//=> {"date": "apr 30,2021"}

或

mySubs ('Jack and Jessica are friends who dicsussed covid-19 testing status upto apr 27,2021')
//=> {"date": "apr 27,2021", "friend-name": "Jessica"}

如果没有匹配，就会产生一个空对象。

我们通过为我们的样本动态生成正则表达式来做到这一点，这些正则表达式将捕获所做的替换：

​

const regEscape = (s) =>
  s .replace (/[-\/\\^$*+?.()|[\]{}]/g, '\\$&');


const makeTester = ({sample, extract, propName}) => ({
  regex: new RegExp (
    regEscape (sample .slice (0, sample .indexOf (extract))) + 
    '(.+)' + 
    regEscape (sample .slice (sample .indexOf (extract) + extract .length))
  ), 
  propName
})

const substitutes = (configs, testers = configs .map (makeTester)) => (sentence) =>
  Object.assign( ...testers .flatMap (({regex, propName}) => {
    const match = sentence .match (regex)
    return (match)
      ? {[propName]: match[1]}
      : {}
  }))

const configs = [{
  sample: 'covid-19 testing status upto may 05,2021',
  extract: 'may 05,2021',
  propName: 'date'
}, {
  sample: 'Jack and Jones are friends',
  extract: 'Jones',
  propName: 'friend-name'
}]

const mySubs = substitutes (configs)

console .log (mySubs ('Jack and William are friends'))
console .log (mySubs ('covid-19 testing status upto apr 30,2021'))
console .log (mySubs ('Jack and Jessica are friends who dicsussed covid-19 testing status upto apr 27,2021'))
console .log (mySubs ('Some random string that does not match'))

.as-console-wrapper {max-height: 100% !important; top: 0}

​

如果还需要报告匹配的模板，可以向每个模板添加一个名称，然后通过以下两个主要函数传递结果：

{"covid": {"date": "apr 27,2021"}, "friends": {"friend-name": "Jessica"}}

它只是稍微复杂一点：

​

const regEscape = (s) =>
  s .replace (/[-\/\\^$*+?.()|[\]{}]/g, '\\$&');


const makeTester = ({name, sample, extract, propName}) => ({
  regex: new RegExp (
    regEscape (sample .slice (0, sample .indexOf (extract))) + 
    '(.+)' + 
    regEscape (sample .slice (sample .indexOf (extract) + extract .length))
  ),
  propName,
  name
})

const substitutes = (configs, testers = configs.map(makeTester)) => (sentence) =>
  Object.assign( ...testers .flatMap (({name, regex, propName}) => {
    const match = sentence .match (regex)
    return (match)
      ? {[name]: {[propName]: match[1]}}
      : {}
  }))

const configs = [{
  name: 'covid', 
  sample: 'covid-19 testing status upto may 05,2021',
  extract: 'may 05,2021',
  propName: 'date'
}, {
  name: 'friends',
  sample: 'Jack and Jones are friends',
  extract: 'Jones',
  propName: 'friend-name'
}]

const mySubs = substitutes (configs)

console .log (mySubs ('Jack and William are friends'))
console .log (mySubs ('covid-19 testing status upto apr 30,2021'))
console .log (mySubs ('Jack and Jessica are friends who dicsussed covid-19 testing status upto apr 27,2021'))
console .log (mySubs ('Some random string that does not match'))

​

不管怎样，这都有一定的局限性。如果模板以奇怪的方式重叠，那么很难搞清楚该怎么做。你也有可能只想匹配完整的句子，而我的双匹配示例就没有意义了。如果是这样的话，您只需在传递给'^'的字符串中添加一个'$'和一个'$'。

同样，这也是对您的需求的猜测。这里最重要的一点是，您可能能够动态生成regexes以供使用。