I'm trying to use D3 to find the lowest value in my dataset. However, I also have values that are 0, but I want D3 to find the lowest value that is not 0.

Currently I am using:

d3.min(data, function(d) {return d.houseValues; })

But obviously this returns 0 sometimes, when a 0 is found.

Is there a way to do this? Or is the only solution to build a normal for-loop with an if-statement to ignore the 0 values..?

Thanks!

I'm trying to use D3 to find the lowest value in my dataset. However, I also have values that are 0, but I want D3 to find the lowest value that is not 0.

Currently I am using:

d3.min(data, function(d) {return d.houseValues; })

But obviously this returns 0 sometimes, when a 0 is found.

Is there a way to do this? Or is the only solution to build a normal for-loop with an if-statement to ignore the 0 values..?

Thanks!

• javascript
• d3.js

3 Answers 3

You can use the constant Infinity, since Math.min(Infinity, someNumber) always return someNumber (unless someNumber is also infinity). So it'll look like this:

smallest = d3.min(data, function(d) {return d.houseValues || Infinity; })

If needed, you can check smallest == Infinity, which would be true in the case that all house values were 0.

Try filtering the data to remove zeroes first, e.g.

var noZeroes = data.filter(function(d) { return d.houseValues !== 0; });
d3.min(noZeroes, function(d) {return d.houseValues; })

Building on @meetamit's answer, if you want smallest to be undefined when the data has all zeros, use undefined instead of Infinity.

d3.min() "ignores undefined, null and NaN values".

const data1 = [
  {
    houseValues: 0,
  },
  {
    houseValues: 100000,
  },
  {
    houseValues: 150000,
  },
];

const data2 = [
  {
    houseValues: 0,
  },
  {
    houseValues: 0,
  },
];

smallest = d3.min(data1, function(d) { return d.houseValues; });

smallestNonZero = d3.min(data1, function(d) { return d.houseValues || undefined });

smallestAllZeros = d3.min(data2, function(d) { return d.houseValues || undefined });


console.log(smallest);
console.log(smallestNonZero);
console.log(smallestAllZeros);

<script src="https://cdnjs.cloudflare./ajax/libs/d3/5.7.0/d3.min.js"></script>