使用正则表达式提取JavaScript中的字符串

Question

I am receiving strings from an external client and I am trying to perform regex-ing to extract a certain number and status that are embedded in this string. Here's the examples of the strings that are coming in.

data = "< REP 1 INPUT_AUDIO_A ON >"
data = "< REP 1 INPUT_AUDIO_A OFF " 
data = "< REP 2 INPUT_AUDIO_A ON >" 
data = "< REP 2 INPUT_AUDIO_A OFF >"

and so on

I am trying to extract 1 , 2 as gate number and the on or off as status in two different variables. I was able to extract numbers with regex as follows.

var gateNumberRegex = /[0-8]/g;
var gateNumber = data.charAt(data.search(gateNumberRegex)); //extract the gate number from string, output is 1 or 2 etc.

Not sure how to extract the on / off status, any pointers?

Answer 1

By itself, ON/OFF may be found using /\\b(ON|OFF)\\b/ but if there may be ON/OFF in another place in those strings, you may go more contextual with /INPUT_AUDIO_A[\\s]+(ON|OFF)/ . Once you apply the regex like this

var match = `/\b(ON|OFF)\b/`.exec(yourLine)

you may extract the on/off bit with

var enabled = match ? match[1] : yourDefaultValue;

Answer 2

Straight forward

(\d+)\s+INPUT_AUDIO_A\s+(ON|OFF)

See a demo on regex101.com .

---

Broken down, this says:

 (\\d+) # capture 1+ digits into group 1 \\s+ # match 1+ whitespaces INPUT_AUDIO_A # INPUT_AUDIO_A literally \\s+ # 1+ whitespaces (ON|OFF) # ON or OFF 

Use group $1 and $2 , respectively as in this snippet:

 var data = 'data = “< REP 1 INPUT_AUDIO_A ON >” or' var match = data.match(/(\\d+)\\s+INPUT_AUDIO_A\\s+(ON|OFF)/) console.log(match[1]) console.log(match[2]) 

Answer 3

You could do something like this:

var onOrOffRegex = /INPUT_AUDIO_A ([^\s]+)/g
var onOrOff = data.match(onOrOffRegex)[1]

Then you could use the onOrOff variable to get the string status of the data.

Answer 4

For your very specific case, assuming the input is "valid", this is the most straight-forward solution:

\d+|ON|OFF

Output: '1','ON','1','OFF','2','ON','2','OFF'

And then you can separate it to "pairs":

 var string = document.getElementById("input").innerHTML; var array = string.match(/\\d+|ON|OFF/g); var result = []; var print = ""; for (i = 0; i < array.length; i += 2) { result += [array[i], array[i + 1]]; print += "[" + array[i] + ", " + array[i + 1] + "]<BR>" } document.getElementById("input").innerHTML = print; 

 <div id="input"> data = “ < REP 1 INPUT_AUDIO_A ON>” or data = “ < REP 1 INPUT_AUDIO_A OFF>” or data = “ < REP 2 INPUT_AUDIO_A ON>” or data = “ < REP 2 INPUT_AUDIO_A OFF>” </div> 

Answer 5

The simplest way to do this would be:

var data = "< REP 1 INPUT_AUDIO_A ON >"

var result = data.match(/\\b(\\d+|ON|OFF)\\b/g)

This will output an array containing the number and the status: ["1", "ON"]