How to prevent rounding in python

Question

suppose if a variable has a float value, and if i re-assign the same variable with an another float value it will round the fractional part of the value with respect to the no of fractional part in first value, how can i prevent that
eg:

wav=10.456878798
print wav
wav=10.555546877796546
print wav

10.456878798
10.5555468778

Asked By: Bijoy

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Source

Answer 1

The problem is not with Python. See print statement prints 10 decimal places of a fraction even though it has more. Just check your variable in python shell, it shall give you the entire value.

>>> wav = 10.232483243243243
>>> print wav
10.2324832432
>>> wav
10.232483243243243

Answered By: Syed Mauze Rehan

Answer 2

You can do the following and set the precision :

$ cat test.py
a = 10.456878798
print "{0:.2f}".format(a)
a = 10.555546877796546
print "{0:.15f}".format(a)

The above will print you :

$ python test.py
10.46
10.555546877796546

Hope this helps.

Answered By: user2360915

Answer 3

None of the solutions provided worked. So I decided to search the Standard Library and found a very useful formula. In order to do so you need to import decimal from the standard library and define the precision of the fractional part as follow. This way you will have 28 digits in the fraction part!

from decimal import *
getcontext().prec = 28

after that in the python shell, you would find as follow:

Decimal(1) / Decimal(7)

Decimal('0.1428571428571428571428571429')

Answered By: Tahere Farhadi

Answer 4

y = 3.1415926535897932384626
y = "{:.6f}".format(y)
y = str(y)
y = y[:-2]
print(y)

Answered By: Tohid Hadinejad

How to prevent rounding in python

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