1 | initial version |

At the beginning of your function, add a line to test if `x`

is integer. Optionally, add a test of how large this integer is if you still want to put large integers in scientific notation.

Optionally, you can also test whether `x`

is a floating-point number equal to zero, in which case you might not want to put it in scientific notation.

Then, you can reduce the number of digits by taking `x.n(digits=4)`

(this will also turn an integer into a floating-point number, which you may want to do for large integers).

You can then apply the method `str`

with the option `no_sci=False`

to make sure to get a scientific notation regardless of the size of `x`

. The method also has an option `skip_zeroes`

.
Learn more about this method by reading the documentation:

```
x = 1.2
x.str?
```

Combining these tricks, your function could look like this:

```
def numprint(x):
if type(x) == sage.rings.integer.Integer or type(x) == int:
if abs(x) < 1000: return sage.misc.latex.LatexExpr(x)
if x == 0.: return LatexExpr('0.')
s = x.n(digits=4).str(no_sci=False).split('e')
s = s[0].replace('.', r',\!') + r' \,\ldotp 10^{' + s[1] + '}'
return sage.misc.latex.LatexExpr(s)
```

I would suggest to check carefully if the output is what you hoped for each in a wide variety of inputs.

```
z = dict()
z[1] = [0, 1, 100, 1000, 10000, 100000, 10000000000000000000]
z[2] = [12, 123, 1234, 12345, 1234567890, 12345678901234567890]
z[3] = [0., 1., 100., 1000., 10000., 100000., 10000000000000000000.]
z[4] = [12., 123., 1234., 12345., 1234567890., 1234567890123456.]
z[5] = [0.00012, 0.12, 1.2, 1.23, 1.234, 1.23456, 1.2345678]
z[6] = [0.00012345678, 1.2345678, 12.345678, 1234.5678, 1234567.8]
z[7] = [1.2345e-2, 1.2345e-1, 1.2345e0, 1.2345e1, 1.2345e3, 1.2345e5]
for a in z:
print '----- test', a, '-----'
for x in z[a]:
print '%30s%30s'%(x,numprint(x))
print ''
```

Having a wide range of different inputs to test is good when you are adjusting your function. Add special cases as needed.

Copyright Sage, 2010. Some rights reserved under creative commons license. Content on this site is licensed under a Creative Commons Attribution Share Alike 3.0 license.