### Question :

Using Python 2.7 how do I round my numbers to two decimal places rather than the 10 or so it gives?

```
print "financial return of outcome 1 =","$"+str(out1)
```

##
Answer #1:

Use the built-in function `round()`

:

```
>>> round(1.2345,2)
1.23
>>> round(1.5145,2)
1.51
>>> round(1.679,2)
1.68
```

Or built-in function `format()`

:

```
>>> format(1.2345, '.2f')
'1.23'
>>> format(1.679, '.2f')
'1.68'
```

Or new style string formatting:

```
>>> "{:.2f}".format(1.2345)
'1.23
>>> "{:.2f}".format(1.679)
'1.68'
```

Or old style string formatting:

```
>>> "%.2f" % (1.679)
'1.68'
```

help on `round`

:

```
>>> print round.__doc__
round(number[, ndigits]) -> floating point number
Round a number to a given precision in decimal digits (default 0 digits).
This always returns a floating point number. Precision may be negative.
```

##
Answer #2:

Since you’re talking about **financial** figures, you *DO NOT WANT* to use floating-point arithmetic. You’re better off using Decimal.

```
>>> from decimal import Decimal
>>> Decimal("33.505")
Decimal('33.505')
```

Text output formatting with new-style `format()`

(defaults to half-even rounding):

```
>>> print("financial return of outcome 1 = {:.2f}".format(Decimal("33.505")))
financial return of outcome 1 = 33.50
>>> print("financial return of outcome 1 = {:.2f}".format(Decimal("33.515")))
financial return of outcome 1 = 33.52
```

See the differences in rounding due to floating-point imprecision:

```
>>> round(33.505, 2)
33.51
>>> round(Decimal("33.505"), 2) # This converts back to float (wrong)
33.51
>>> Decimal(33.505) # Don't init Decimal from floating-point
Decimal('33.50500000000000255795384873636066913604736328125')
```

**Proper way to round financial values**:

```
>>> Decimal("33.505").quantize(Decimal("0.01")) # Half-even rounding by default
Decimal('33.50')
```

It is also common to have other types of rounding in different transactions:

```
>>> import decimal
>>> Decimal("33.505").quantize(Decimal("0.01"), decimal.ROUND_HALF_DOWN)
Decimal('33.50')
>>> Decimal("33.505").quantize(Decimal("0.01"), decimal.ROUND_HALF_UP)
Decimal('33.51')
```

Remember that if you’re simulating return outcome, you possibly will have to round at each interest period, since you can’t pay/receive cent fractions, nor receive interest over cent fractions. For simulations it’s pretty common to just use floating-point due to inherent uncertainties, but if doing so, always remember that the error is there. As such, even fixed-interest investments might differ a bit in returns because of this.

##
Answer #3:

You can use `str.format()`

, too:

```
>>> print "financial return of outcome 1 = {:.2f}".format(1.23456)
financial return of outcome 1 = 1.23
```

##
Answer #4:

When working with pennies/integers. You will run into a problem with 115 (as in $1.15) and other numbers.

I had a function that would convert an Integer to a Float.

```
...
return float(115 * 0.01)
```

That worked most of the time but sometimes it would return something like `1.1500000000000001`

.

So I changed my function to return like this…

```
...
return float(format(115 * 0.01, '.2f'))
```

and that will return `1.15`

. Not `'1.15'`

or `1.1500000000000001`

(returns a float, not a string)

I’m mostly posting this so I can remember what I did in this scenario since this is the first result in google.

##
Answer #5:

The best, I think, is to use the format() function:

```
>>> print("financial return of outcome 1 = $ " + format(str(out1), '.2f'))
// Should print: financial return of outcome 1 = $ 752.60
```

But I have to say: don’t use round or format when working with financial values.

##
Answer #6:

When we use the round() function, it will not give correct values.

you can check it using,

round (2.735) and round(2.725)

please use

```
import math
num = input('Enter a number')
print(math.ceil(num*100)/100)
```

##
Answer #7:

```
print "financial return of outcome 1 = $%.2f" % (out1)
```

##
Answer #8:

A rather simple workaround is to convert the float into string first, the select the substring of the first four numbers, finally convert the substring back to float.

For example:

```
>>> out1 = 1.2345
>>> out1 = float(str(out1)[0:4])
>>> out1
```

May not be super efficient but simple and works 🙂