Seth Koberg - 10 months ago 46

Python Question

I've been working on a script that takes data from an XLS spreadsheet, rounds the numbers, and removes the decimal point, ex: 2606.89579999999 becomes 26069; However, I need the number to round to two decimal places even if there would be a trailing zero, so 2606.89579999999 should become 260690.

I currently have it so

`i`

`i = round(i, 2)`

I've tried figuring out how to get this to work with

`Decimal`

All other numbers that get rounded, if the rounded value doesn't end in '0', work fine with

`round(i, 2)`

Answer

As you are talking about trailing zeros, this is a question about representation as string, you can use

```
>>> "%.2f" % round(2606.89579999999, 2)
'2606.90'
```

Or use modern style with `format`

function:

```
>>> '{:.2f}'.format(round(2606.89579999999, 2))
'2606.90'
```

and remove point with `replace`

or `translate`

(`_`

refers to result of previous command in python console):

```
>>> _.translate(None, '.')
'260690'
```

Note that rounding is not needed here, as `.2f`

format applyies the same rounding:

```
>>> "%.2f" % 2606.89579999999
'2606.90'
```

But as you mentioned excel, you probably would opt to roll your own rounding function, or use decimal, as `float.round`

can lead to strange results due to float representation:

```
>>> round(2.675, 2)
2.67
>>> round(2606.89579999999, 2)
2606.89
```

With decimal use quantize:

```
>>> from decimal import *
>>> x = Decimal('2606.8950000000001')
# Decimal('2606.8950000000001')
>>> '{}'.format(x.quantize(Decimal('.01'), rounding=ROUND_HALF_EVEN))
'2606.90'
```

That, for your original task, becomes:

```
>>> x = Decimal('2606.8950000000001')
>>> int((x*100).quantize(1, rounding=ROUND_HALF_EVEN))
260690
```

And the reason of strange rounding comes to the front with `Decimal`

:

```
>>> x = Decimal(2606.8950000000001)
# Decimal('2606.89499999999998181010596454143524169921875') # internal float repr
```