Currently I am trying to solve a problem, where I am supposed to print the answer upto two decimal points without rounding off. I have used the below code for this purpose
import math
a=1.175 #value of a after some division
print(math.floor(a*100)/100)
The output we get is:
1.17 #Notice value which has two decimal points & not rounded
But the real problem starts when I try to print a number which is evenly divisible, after the decimal point only one zero is displayed. I have used the same code as above, but now
a=25/5 #Now a is perfectly divisible
print(math.floor(a*100)/100)
The output displayed now is
5.0 #Notice only one decimal place is printed
what must be done rectify this bug?
>Solution :
The division works and returns adequate precision in result.
So your problem is just about visualization or exactly:
- string-representation of floating-point numbers
Formatting a decimal
You can use string-formatting for that.
For example on Python 3, use f-strings:
twoFractionDigits = f"{result:.2f}"
or print(f"{result:.2f}")
See also:
Try on the Python-shell:
Python 3.6.9 (default, Dec 8 2021, 21:08:43)
[GCC 8.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import math
>>> a=1.175 #value of a after some division
>>> result = math.floor(a*100)/100
>>> result
1.17
>>> print(result)
1.17
>>> a=25/5 #Now a is perfectly divisible
>>> result = math.floor(a*100)/100
>>> result
5.0
>>> print(result)
5.0
>>> print(f"{result:.2f}")
5.00
Formatting a decimal as percentage
Similar you can represent the ratio as percentage:
print(f"{result:.2f} %")
prints:
5.00 %
A formatting shortcut for percentage can be:
print(f"{25/100:.2%}")
Which converts the result of 25/100 == 0.25
to:
25.00%
Note: The formatting-literal .2%
automatically converts from ratio to percentage with 2 digits after the decimal-point and adds the percent-symbol.
Formatting many decimals in fixed width (leading spaces)
Another example is to print multiple decimals, like in a column as right-aligned, so you can easily compare them.
Then use string-formatting literal :6.2f
to add leading spaces (here a fixed-width of 6):
>>> print(f"{result:6.2f} %")
5.00 %
>>> print(f"{100/25*100:6.2f} %")
400.00 %
>>> print(f"{25/100*100:6.2f} %")
25.00 %
All this can also be done using %-formatting (compatible with Python before 3.6) as in theherk’s answer.