CODEWITHSUNDEEP
pythonpython-2.7
dassau
dassau

Reputation: 141

how can I round a value with 1 decimal to 2 decimals

I need to round values to exactly 2 decimals, but when I use round() it doesn't work, if the value is 0.4, but I need 0.40. 

round(0.4232323, 2) = 0.42
bad: round(0.4, 2) = 0.4

How can I solve this?

Upvotes: 1

Views: 3445

Answers (3)

Joe
Joe

Reputation: 47749

If you represent these values as floats then there is no difference between 0.4 and 0.40. To print them with different precision is just a question of format strings (as per the other two answers).

However, if you want to work with decimals, there is a decimal module in Python.

>>> from decimal import Decimal
>>> a = Decimal("0.40")
>>> b = Decimal("0.4")
# They have equal values
>>> a == b
True 

# But maintain their precision
>>> a + 1
Decimal('1.40')

>>> b + 1
Decimal('1.4') 

>>> a - b
Decimal('0.00')

Use the quantize method to round to a particular number of places. For example:

>>> c = Decimal(0.4232323)
>>> c.quantize(Decimal("0.00"))
Decimal('0.42')
>>> str(c.quantize(Decimal("0.00")))
'0.42'

Upvotes: 1

user817530
user817530

Reputation: 

print("{0:.2f}".format(round(0.4232323, 2)))

Upvotes: 1

nneonneo
nneonneo

Reputation: 179717

0.4 and 0.40 are mathematically equivalent.

If you want to display them with two decimal places, use {:.2f} formatting:

>>> '{:.2f}'.format(0.4)
'0.40'

Upvotes: 7

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