# Extract specific text and associated value from a string?

**URL:** <https://discourse.nodered.org/t/extract-specific-text-and-associated-value-from-a-string/12707>\
**Category:** General\
**Created:** [28 June 2019 20:24 UTC](https://discourse.nodered.org/t/extract-specific-text-and-associated-value-from-a-string/12707 "2019-06-28T20:24:32Z")\
**Posts on this page:** 16\
**Page:** 1

<div class="post-metadata">

**Author:** ![nodecentral](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/nodecentral/32/10432_2.png) [@nodecentral](https://discourse.nodered.org/u/nodecentral)\
**Post date:** [28 June 2019 20:24 UTC](https://discourse.nodered.org/t/extract-specific-text-and-associated-value-from-a-string/12707/1 "2019-06-28T20:24:32Z")

</div>

Hi,

I’m struggling with this one;

I able to receive a very long string on the status of my HDMI matrix, and what I want to do is extract sections of it to create new/separate payloads to then work with .

Here’s an example of the string produced,

> ========================================================================================================= = **Systems STATUS** \*= =---------------------------------------- ---------------------------------------------------------------= = Systems information F/W Version : 1.10 = =------------------------------------------------------------------------------------ -------------------= = Power :ON = = Cascading Mode :Disable = =------------------ -------------------------------------------------------------------------------------= = Network Setting Status : = = MAC Address = 7Q:CB:E2:90:05:CA = = Host IP Address = 192.168.111.172 = = Net Mask = 255.255.255.000 = = Router IP Address = 192.168.111.001 = = TCP Port = 0023 = = DHCP : ON = =-------------------------------------------------------------------------------------------------------= = Video Input Setup Status : = = Video Input 01 : EDID = DEFAULT 01, LINK = ON = = Video Input 02 : EDID : User01 EDID, LINK = ON = = Video Input 03 : EDID : User01 EDID, LINK = ON = = Video Input 04 : EDID = DEFAULT 01, LINK = OFF = =-------------------------------------------------- -----------------------------------------------------= = Video Output Setup Status : = = Video Output 01 : Input = 01, Output = ON , LINK = OFF = = Video Output 02 : Input = 01, Output = ON , LINK = ON = = Video Output 03 : Input = 02, Output = ON , LINK = OFF = = Video Output 04 : Inp ut = 01, Output = ON , LINK = OFF = =-------------------------------------------------------------------------------------------------------= = Audio Output Setup Status : = = Audio Output 01 : Analog = Enabled, Digital = Enabled = = Audio Output 02 : Analog = Enabled, Digital = Enabled = = Audio Output 03 : Analog = Enabled, Digital = Enabled = = Audio Output 04 : Analog = Enabled, Digitaled ------------------------------ =\*\*\*\*\*\*\*========================================

I’d like to have created an individual payload for each of the video outputs, one for the text and one focused on the specific output value,

So, for example, 8 individual payloads would be created out of the long string above,

Payload 1 = Video Output 01 : Input = 03  
Payload 2 = 3

Payload 3 = Video Output 02 : Input = 02  
Payload 4 = 2

Payload 5 = Video Output 03 : Input = 02  
Payload 6 = 2

Payload 7 = Video Output 04 : Input = 01  
Payload 8 = 1

---

<div class="post-metadata">

**Author:** ![Colin](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/colin/32/17040_2.png) [@Colin](https://discourse.nodered.org/u/Colin)\
**Post date:** [28 June 2019 21:02 UTC](https://discourse.nodered.org/t/extract-specific-text-and-associated-value-from-a-string/12707/2 "2019-06-28T21:02:00Z")

</div>

To be certain what we are dealing with can you feed that into a debug node and show us what it looks like?

---

<div class="post-metadata">

**Author:** ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\
**Post date:** [28 June 2019 21:02 UTC](https://discourse.nodered.org/t/extract-specific-text-and-associated-value-from-a-string/12707/3 "2019-06-28T21:02:53Z")

</div>

I'd start with regex.

Go [Here](https://regex101.com/) and develop a capture regex then copy regex from that into a function that outputs your payloads.

Google is your friend. Loads of how tos for js + regex.

If you get stuck, post your progress and others will assist.

---

<div class="post-metadata">

**Author:** ![nodecentral](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/nodecentral/32/10432_2.png) [@nodecentral](https://discourse.nodered.org/u/nodecentral)\
**Post date:** [28 June 2019 21:12 UTC](https://discourse.nodered.org/t/extract-specific-text-and-associated-value-from-a-string/12707/4 "2019-06-28T21:12:38Z")

</div>

Hi @Colin

it’s a bit of a mess in the debug window, as the matrix sends the information in a batch, which i then merge/join into one long string to work with ;

Here’s how it ‘a first received (after it’s converted to a string)

 ![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/2X/2/282c59aba979b1bcc10861167f7d5785eb58f625.jpeg)

---

<div class="post-metadata">

**Author:** ![zenofmud](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/zenofmud/32/316_2.png) [@zenofmud](https://discourse.nodered.org/u/zenofmud)\
**Post date:** [28 June 2019 21:18 UTC](https://discourse.nodered.org/t/extract-specific-text-and-associated-value-from-a-string/12707/5 "2019-06-28T21:18:45Z")

</div>

You could use a change node to  
change msg.payload 'replace' all `=` with nothing and  
change msg.payload replace all `*` with nothing and  
change msg.payload replace all `*` with nothing and  
change msg.payload replace all `Video Output Setup Status` with 'VO Setup Status`change msg.payload replace all`Video Output`with '*Video Output`

feed that into a split node and split on `*`

Toss out the first message - that will remove a bunch of the clutter. The next four msg's will have your info and you can interrogate it and so what you want with it.

---

<div class="post-metadata">

**Author:** ![nodecentral](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/nodecentral/32/10432_2.png) [@nodecentral](https://discourse.nodered.org/u/nodecentral)\
**Post date:** [28 June 2019 21:23 UTC](https://discourse.nodered.org/t/extract-specific-text-and-associated-value-from-a-string/12707/6 "2019-06-28T21:23:38Z")

</div>

Thanks, i’ll look into that, I also will look again at regex now that I have that link, that looks pretty cool,

Using that tool, I could quickly see that the following regex could match to the parts within the string I’m looking for. But what node do I use to extract those parts so they become their own individual payloads ?

`Video Output 0\d : Input = 0\d”`

Also - looking at the debug, i’ve just noticed that each payload sent by my Matrix is 255 characters ? Is that something I can work with;, can I set some sort of buffer to capture them all, in order, rather than process them one by one ?

---

<div class="post-metadata">

**Author:** ![zenofmud](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/zenofmud/32/316_2.png) [@zenofmud](https://discourse.nodered.org/u/zenofmud)\
**Post date:** [28 June 2019 22:47 UTC](https://discourse.nodered.org/t/extract-specific-text-and-associated-value-from-a-string/12707/7 "2019-06-28T22:47:04Z")

</div>

There is a section in `settings.js` that will allow you to show longer data fields in the debug sidebar:

> ```
> // The maximum length, in characters, of any message sent to the debug sidebar tab
> debugMaxLength: 1000,
> 
> ```

you can increase it but you will need to stop/start NR.

---

<div class="post-metadata">

**Author:** ![nodecentral](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/nodecentral/32/10432_2.png) [@nodecentral](https://discourse.nodered.org/u/nodecentral)\
**Post date:** [28 June 2019 23:21 UTC](https://discourse.nodered.org/t/extract-specific-text-and-associated-value-from-a-string/12707/8 "2019-06-28T23:21:56Z")

</div>

> [@zenofmud](#):
>
> There is a section in `settings.js` that will allow you to show longer data fields in the debug sidebar:

Thanks, that’s good to know, but by the looks of things it’s the HDMI Matrix that’s choosing to send its Status report in chunks ? Are you aware how I can seem less combine them all into one automatically ?

---

<div class="post-metadata">

**Author:** ![zenofmud](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/zenofmud/32/316_2.png) [@zenofmud](https://discourse.nodered.org/u/zenofmud)\
**Post date:** [29 June 2019 07:57 UTC](https://discourse.nodered.org/t/extract-specific-text-and-associated-value-from-a-string/12707/9 "2019-06-29T07:57:13Z")

</div>

I thought you were already joining the data together??

---

<div class="post-metadata">

**Author:** ![nodecentral](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/nodecentral/32/10432_2.png) [@nodecentral](https://discourse.nodered.org/u/nodecentral)\
**Post date:** [29 June 2019 08:18 UTC](https://discourse.nodered.org/t/extract-specific-text-and-associated-value-from-a-string/12707/10 "2019-06-29T08:18:23Z")

</div>

Yep, I’m using a join node - but I’m noticing each join introduces a space to the eventual combined string; so if any of the 255 character payloads from the Matrix are broken up and sent mid-word - I will get part of it in one payload and the rest in the other - with that space in between.

You can see examples in the completed joined up string posted earlier - the word “input” became “inp’ and “ut”

Just curious if there was another way to do it.

---

<div class="post-metadata">

**Author:** ![dceejay](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/dceejay/32/38_2.png) [@dceejay](https://discourse.nodered.org/u/dceejay)\
**Post date:** [29 June 2019 08:39 UTC](https://discourse.nodered.org/t/extract-specific-text-and-associated-value-from-a-string/12707/11 "2019-06-29T08:39:23Z")

</div>

you can set any character you like to join strings with

---

<div class="post-metadata">

**Author:** ![zenofmud](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/zenofmud/32/316_2.png) [@zenofmud](https://discourse.nodered.org/u/zenofmud)\
**Post date:** [29 June 2019 08:54 UTC](https://discourse.nodered.org/t/extract-specific-text-and-associated-value-from-a-string/12707/12 "2019-06-29T08:54:27Z")

</div>

You could pass the input msgs thru node-red-contrib-string (using the method `trimLeft()`) before joinging the msgs together. That would trim out all leading spaces.

---

<div class="post-metadata">

**Author:** ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\
**Post date:** [29 June 2019 09:20 UTC](https://discourse.nodered.org/t/extract-specific-text-and-associated-value-from-a-string/12707/13 "2019-06-29T09:20:43Z")

</div>

I have had a play but before the grand reveal, some questions...

1. What is the make and model of this device - perhaps they have an alterative interface or output format?
2. Is this data streaming continuously? Serial? TCP???. If so, then perhaps you could find a suitable character (or characters) to `split` on so that data is broken up more meaningfully.

**So, what i did...**  
To get you started, I have written some base code you can use to build usable objects from that string e.g...

The results will be JS objects that look like this...

```auto
//the video output object

{ output1: { input: 1, output: 'ON', link: 'OFF' },
  output2: { input: 1, output: 'ON', link: 'ON' },
  output3: { input: 2, output: 'ON', link: 'OFF' } 
}

//the audio output object
{
  output1: { analog: 'Enabled', digital: 'Enabled' },
  output2: { analog: 'Enabled', digital: 'Enabled' },
  output3: { analog: 'Enabled', digital: 'Enabled' }  
}

```

Meaning you can access them like this...  
`msg.payload.output1.input //1`  
`msg.payload.output2.output) // ON`  
`msg.payload.output3.link // OFF`

  

**NOTE...**  
/Your data appears to have corruption hence not finding output4 on the Video and the Audio string.

  

**The nitty gritty...**  
If you add the below code to a function block with 2 outputs, you should get Video outputs on output pin 1 & Audio outputs on output pin 2 (I'll let you extend it)

**The code for the function block...**

```auto
var s = msg.payload; //the string to parse

//the regex we use to find video output parts
var videoOutputRegex = /Video Output\D*(\d*).*?Input\D*(\d*).*?Output\W*=\W*(\w*).*?LINK\W*=\W*(\w*)/gm;
// Alt format, less strict
// var videoOutputRegex = /Video Output (\d*) :\W*\D*(\d*)\W*.*?= (\w*)\W*.*?= (\w*)|/gm;

//the regex we use to find audio output parts
var audioOutputsRegex = /Audio Output\D*(\d*).*?Analog\W*=\W*(\w*).*?Digital\W*=\W*(\w*)/gm;

//function to get all matches and thier group items
function getMatches(string, regex) {
  let _matches = [];
  let _match;
  while (_match = regex.exec(string)) {
    _matches.push([..._match]);
  }
  return _matches;
}

//node.warn(matches)

//build an object named video and add properties .output1, .output2 etc.
var video = {};
var vomatches = getMatches(s,videoOutputRegex);
vomatches.forEach(function(m){
  let no = parseInt(m[1]);
  let name = "output" + no;
  if(m.length >= 4){
    video[name] = {
      input: parseInt(m[2]),
      output: m[3],
      link: m[4]
    }
  }
})

//build an object named audio and add properties .output1, .output2 etc.
var audio = {};
var aomatches = getMatches(s,audioOutputsRegex);
aomatches.forEach(function(m){
  let no = parseInt(m[1]);
  let name = "output" + no;
  if(m.length >= 4){
    audio[name] = {
      analog: m[2],
      digital: m[3]
    }
  }
})

//now you can access elements like...
// video.output1.input // 1
// video.output2.output // ON
// video.output3.link // OFF

//view the whole object
node.warn(video)
/*
{ output1: { input: 1, output: 'ON', link: 'OFF' },
  output2: { input: 1, output: 'ON', link: 'ON' },
  output3: { input: 2, output: 'ON', link: 'OFF' } 
}

*/
//view the whole object
node.warn(audio)
/*
{
  output1: { analog: 'Enabled', digital: 'Enabled' },
  output2: { analog: 'Enabled', digital: 'Enabled' },
  output3: { analog: 'Enabled', digital: 'Enabled' }  
}
*/

//build the 2 output messages for pin1 and pin2
let msg1 = {
  topic: "video/outputs",
  payload: video
}
let msg2 = {
  topic: "audio/outputs",
  payload: audio
}

return [msg1,msg2]; //remember to set 2 outputs for this function node

```

**Want to see it in action & have a play before incorporating it into node-red?**...  
[see node js playground here](https://repl.it/@StephenMcLaughl/Parse-HDMI-Matrix-String).

---

<div class="post-metadata">

**Author:** ![nodecentral](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/nodecentral/32/10432_2.png) [@nodecentral](https://discourse.nodered.org/u/nodecentral)\
**Post date:** [29 June 2019 09:31 UTC](https://discourse.nodered.org/t/extract-specific-text-and-associated-value-from-a-string/12707/14 "2019-06-29T09:31:07Z")

</div>

Thanks @Steve-Mcl

I’ll take a look at your suggestion

Here’s the answers to your questions.

> [@Steve-Mcl](#):
>
> ...
> 
> 1. What is the make and model of this device - perhaps they have an alterative interface or output format? **A: it’s a SY Electronics MUHD44 , RS232 and Ethernet interface only**
> 2. Is this data streaming continuously? Serial? TCP???. If so, then perhaps you could find a suitable character (or characters) to `split` on so that data is broken up more meaningfully. **A: I’m connecting via TCP/Telnet 23 - and the data is provided upon request when an ascii command is sent**

---

<div class="post-metadata">

**Author:** ![nodecentral](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/nodecentral/32/10432_2.png) [@nodecentral](https://discourse.nodered.org/u/nodecentral)\
**Post date:** [29 June 2019 09:43 UTC](https://discourse.nodered.org/t/extract-specific-text-and-associated-value-from-a-string/12707/15 "2019-06-29T09:43:42Z")

</div>

Ok, this is looking very interesting now ....

I’ve added your code to a function, but with only one debug node, as I’m not sure what you mean about adding two; when there’s only one outlet coming from the function mode ?

 ![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/2X/f/fced13909a8d2b7001bf64d65654dee28364cac6.jpeg)

---

<div class="post-metadata">

**Author:** ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\
**Post date:** [29 June 2019 10:15 UTC](https://discourse.nodered.org/t/extract-specific-text-and-associated-value-from-a-string/12707/16 "2019-06-29T10:15:10Z")

</div>

Where you enter the code in the function node, below the code window there is a number spinner. Set it to two.

Alternatively, you can output the two objects on 1 msg...

```auto
msg.videoOutputs = video;
msg.audioOutputs = audio;
return msg;

```