p5.js - JavaScript select same row, multi columns (CSV)

Question

This is is P5.js and it's a very stupid and simple problem. https://editor.p5js.org/kornfusion/sketches/5xtb88Ntn

  for (let i = 0; i < table.getRowCount(); i++){
    for (let j = 0; j < table.getRowCount(); j++){
    if (table.getRow(i).arr[1] = '00:11:1F:AC:ba:39') {
      j = table.getRowCount(i).length;
      textSize(155);
      text(table.getRow(i).arr[2], 400, 540);
    }
  }
}

I'm trying to match the mac address with IP. and if they matched put them beside the circle. The circles are already in the sketch, All I need is the data from CSV file and go through each row to find MAC.

Answer 1

The description is confusing alongside the code.

I'm trying to match the mac address with IP. and if they matched put them beside the circle.

Do you mean match a section of the MAC address to a section of the IP address ?

A MAC address in your example looks like this: 00:11:1f:10:11:13.

An IP address in your example looks like this: 10.11.2.1.

Do you mean compare the parts that aren't the same across rows (e.g. 00:11:1f:10:11:13 to 10.11.2.1 )?

Your conditions suggests otherwise:

if (table.getRow(i).arr[1] = '00:11:1F:AC:ba:39')

It attempts to match any row with MAC address 00:11:1F:AC:ba:39. Notice that arr[1] points to the second CSV column: "Model". The MAC address is the forth column (at index 3 (e.g. table.getRow(i).arr[3])) Alternatively you can retrieve it by colum name since the CSV has a header:

table.getRow(i).obj["MAC address"]

If you're looping through all the rows a single for loop should do. Additionally you need to handle the edge case of the MAC address not being in the list.

e.g.

  let foundIP = null;
  for (let i = 0; i < table.getRowCount(); i++){
      let currentRow = table.getRow(i);
      if (currentRow.obj['MAC address'] === '00:11:1F:AC:ba:39'){
        foundIP = currentRow.obj['IP address'];
        break;
      }
    }

  
  if(foundIP){
    console.log('foundIP',foundIP);
  }else{
    console.log('no IP found for MAC 00:11:1F:AC:ba:39');
  }

Notice that:

• currentRow is re-used (as opposed to calling table.get() multiple times per loop): this pays off especially when you have to process many rows
• in JS == works, but === is recommended since it also checks if the data type matches
• break is used to break out of the for loop once a match has been found. (if it hasn't foundRow will not have a valid value)

This can easily be encapsulated in a re-usable function:

function findIP(table, macAddress) {
  for (let i = 0; i < table.getRowCount(); i++) {
    let currentRow = table.getRow(i);
    if (currentRow.obj['MAC address'] === macAddress) {
      return currentRow.obj['IP address'];
    }
  }
}

In this case, the result is either the IP (if found) or undefined (if no matches were found):

  let macToFind = '00:11:1F:AC:ba:39'
  let foundIP = findIP(table, macToFind);

  if (foundIP) {
    console.log('foundIP', foundIP);
  } else {
    console.log('no IP found for MAC ' + macToFind);
  }

This should make it flexible enough to search multiple tables and mac addresses if needed.