Python3 ex5 related question

Python
#1

Hi,
I am new to programming. Why are these codes output have different values? I already search and cannot find the related explain or may be I cannot understand their meanings.

Code = Result
print(1 + 2) = 3
print(1 + 2.2) = 3.1
print(1.1 + 2.2) = 3.3000000000000003

Thanks,
atr

#2

Hmmm that’s odd. I can not replicate the second result as mine calculates correctly as a float.

The third result is really odd. I know you get odd results with integer division but I’ve not seen this before with addition. Following thread for insight. Perhaps @zedshaw can enlighten us…

def add(a,b):
    return a + b
    
print(add(1, 2))
print(add(1, 2.2))
print(add(1.1, 2.2))

Results:

3
3.2
3.3000000000000003
Execution completed in 5ms.
1 Like
#3

Aha!!! Found this: https://docs.python.org/3/tutorial/floatingpoint.html

2 Likes
#4

So that’s correct but the final one is probably surprising. Honestly that’s just because computer suck at floating point math by default. If you want very accurate floating point then you use:

https://docs.python.org/3/library/decimal.html

1 Like