exponential float formmating

[zunbeltz]

Hi,

For compatibility reasons with an old program I have to format string
in exponential
format with the following format

0.xxxxxE-yy

This means that the number start always by 0 and after the exponent
there should be alway the sing and 2 number for the exponent.

for example 13 shoud be 0.13000E+02
I always get 1.30000E001

Thanks,

Zunbeltz

 

[Marc 'BlackJack' Rintsch]

For compatibility reasons with an old program I have to format string
in exponential format with the following format

0.xxxxxE-yy

This means that the number start always by 0 and after the exponent
there should be alway the sing and 2 number for the exponent.

for example 13 shoud be 0.13000E+02
I always get 1.30000E001

I don't know if this is platform dependent but this works for me:

In [41]: '%e' % 1.3
Out[41]: '1.300000e+00'

In [42]: ('%e' % 1.3).upper()
Out[42]: '1.300000E+00'

Ciao,
Marc 'BlackJack' Rintsch

 

[zunbeltz]

For compatibility reasons with an old program I have to format string
in exponential format with the following format

This means that the number start always by 0 and after the exponent
there should be alway the sing and 2 number for the exponent.

for example 13 shoud be 0.13000E+02
I always get 1.30000E001

I don't know if this is platform dependent but this works for me:

In [41]: '%e' % 1.3
Out[41]: '1.300000e+00'

In [42]: ('%e' % 1.3).upper()
Out[42]: '1.300000E+00'

Ciao,
Marc 'BlackJack' Rintsch

I am working in windows I get'1.300000e+001'

In all cases I need the number to start with 0
0.13000E+01

 

[attn.steven.kuo]

Hi,

For compatibility reasons with an old program I have to format string
in exponential
format with the following format

0.xxxxxE-yy

This means that the number start always by 0 and after the exponent
there should be alway the sing and 2 number for the exponent.

for example 13 shoud be 0.13000E+02
I always get 1.30000E001

Perhaps it would then be worthwhile to subclass float?

import math
class ffloat(float):
"""Formatted float?"""
def __str__(self):
prefix = (self < 0) and '-' or ''
fabs = math.fabs(self)
exponent = math.floor(math.log10(fabs)) + 1
significand = fabs / math.pow(10, exponent)
width = exponent > 0 and 2 or 3
return '%s%fE%0*d' % (prefix,significand,width,exponent)


f = ffloat(13)
print f
f = ffloat(-12.23e-4)
print f

 

[Steven D'Aprano]

For compatibility reasons with an old program I have to format string
in exponential format with the following format

0.xxxxxE-yy

This means that the number start always by 0 and after the exponent
there should be alway the sing and 2 number for the exponent.

for example 13 shoud be 0.13000E+02
I always get 1.30000E001

I don't know if this is platform dependent but this works for me:

In [41]: '%e' % 1.3
Out[41]: '1.300000e+00'

In [42]: ('%e' % 1.3).upper()
Out[42]: '1.300000E+00'

Alas, you've missed the Original Poster's requirement that the formatted
number always starts with 0.

Also, an easier way to format floats with a capital E is to use %E
instead of %e.

I don't believe there is a standard way of formatting floats with a
leading zero.

 

[Lawrence D'Oliveiro]

In message <[email protected]>,

In all cases I need the number to start with 0
0.13000E+01

So why not move the decimal point left one, and add one to the exponent.

 

[Dennis Lee Bieber]

I don't believe there is a standard way of formatting floats with a
leading zero.

Except, possibly, in FORTRAN... which, as I recall, had formatting
codes to define the scaling before the decimal...
--
Wulfraed Dennis Lee Bieber KD6MOG
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HTTP://wlfraed.home.netcom.com/
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