Question

I am experiencing a problem when trying to use the getcontext().prec = 2 function, trying to get decimal results with only 2 decimals. I have experimented with several variations, but don’t know why I can’t transform float to string inside one of my lists. I am new using Python (2.6), and have not been able to find a solution for this. Thanks in advance for any help.

from __future__ import division
from decimal import *

getcontext().prec = 2

list_a = ['abc','def','ghi']
list_b = [123, 534, 345]
list_c = [Decimal(str(1/6)), Decimal(str(1/1234)), Decimal(str(2/9))]

for r,c,p in zip(list_a, list_b, list_c):
  print '{0} goes with {1} and with {2}%.'.format(r,c,p)

Returns

SyntaxError: Invalid syntax

If I eliminate the str() from the print line, the results are printed, but w/o constraints in the number of decimals. If I use Decimal() – w/o using str first, I get

'first convert the float to a string'. 

Any insights?
Cheers

Answer 1

Decimal(str((2/9))

should be

Decimal(str(2/9))

You have an unclosed ) in the code shown in the example.

To display only two decimal places:

from __future__ import division
from decimal import *

getcontext().prec = 2

list_a = ['abc','def','ghi']
list_b = [123, 534, 345]
list_c = [Decimal(str(1/6)), Decimal(str(1/1234)), Decimal(str(2/9))]
for r,c,p in zip(list_a, list_b, list_c):
  print '{0} goes with {1} and with {2:.2f}%.'.format(r,c,p)