Formatting integers and floats inside strings in python

Question

I'm trying to figure out how to print formatted strings rounding to significant figures. Say I have:

x = 8829834.123

And I want to print it rounded to four sig figs, as an integer. I tried:

print "%4d"%x

and I just get:

Why won't it display:

8829000?

I thought that was how string formatting worked.

Have a look at this question: http://stackoverflow.com/questions/3348825/how-to-round-integers-in-python. You could consider the use of round() as mentioned in the accepted answer. — Bharat, Dec 17 '12 at 07:02
possible duplicate? http://stackoverflow.com/questions/9415939/how-can-i-print-many-significant-figures-in-python — Drew Verlee, Dec 17 '12 at 07:02

score 4 · Answer 1 · answered Dec 17 '12 at 07:32

4

To round to 4 significant digits:

f = float("%.4g" % 8829834.123)

To print it as an integer:

print "%.0f" % f
# -> 8830000

answered Dec 17 '12 at 07:32

jfs

score 2 · Answer 2 · answered Dec 17 '12 at 07:19

2

Format Specifier does not support integer rounding, there may be some solutions but not out of the Box, here are couple of them

>>> print "{:d}000".format(int(x/1000))
8829000
>>> print "{:d}".format(int(round(x,-3)))
8830000

answered Dec 17 '12 at 07:19

Abhijit

It won't produce result rounded to 4 significant digits if `x` has different order of magnitude e.g., `123456789` – jfs Dec 17 '12 at 07:37

2 Answers2