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Show full (non-scientific-notation) of very small decimal?

asked 2016-03-30 04:10:36 +0200

notfed gravatar image

When I run:

1/(2^70).n()

Sage returns:

8.47032947254300e-22

How can I get it to instead show:

.000000000000000000000847032947254300
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answered 2016-03-31 11:07:22 +0200

tmonteil gravatar image

You can look at the no_sci option of the str method of a floating-point number:

sage: a = 1/(2^70).n()
sage: a
8.47032947254300e-22
sage: a.str(no_sci=2)
'0.000000000000000000000847032947254300'

To get the doc of the str method, you can do a.str?

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Comments

Wow, I never knew about this!

kcrisman gravatar imagekcrisman ( 2016-03-31 15:30:38 +0200 )edit
1

answered 2016-03-31 09:42:16 +0200

slelievre gravatar image

updated 2016-03-31 09:57:43 +0200

One possibility to get what you want is to use Python string formatting.

This can be done the old way with % and the new way with {}and .format. The old way will accept many types of numbers, the new way requires the entry to have the type of a Python float.

Here is an illustration of both, with 72 digits after the decimal point.

sage: a = 1/2^70
sage: '%.72f' % a
'0.000000000000000000000847032947254300339068322500679641962051391601562500'
sage: '{:.72f}'.format(float(a))
'0.000000000000000000000847032947254300339068322500679641962051391601562500'

Combine with print to get those displayed without the surrounding ' quotes.

sage: a = 1/2^70
sage: aa = '%.72f' % a
sage: print(aa)
0.000000000000000000000847032947254300339068322500679641962051391601562500
sage: ab = '{:.72f}'.format(float(a))
sage: print(ab)
0.000000000000000000000847032947254300339068322500679641962051391601562500

Related reading:

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Asked: 2016-03-30 04:09:23 +0200

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Last updated: Mar 31 '16