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-   -   How convert string '1e7' to an integer? (http://www.velocityreviews.com/forums/t704576-how-convert-string-1e7-to-an-integer.html)

Peng Yu 11-08-2009 01:17 AM

How convert string '1e7' to an integer?
 
It seems that int() does not convert '1e7'. I'm wondering what
function to use to convert '1e7' to an integer?

>>> int('1e7')

Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ValueError: invalid literal for int() with base 10: '1e7'

Mensanator 11-08-2009 01:41 AM

Re: How convert string '1e7' to an integer?
 
On Nov 7, 7:17*pm, Peng Yu <pengyu...@gmail.com> wrote:
> It seems that int() does not convert '1e7'.


Because 'e' isn't a valid character in base 10.

> I'm wondering what
> function to use to convert '1e7' to an integer?
>
> >>> int('1e7')


>>> int(1e7)

10000000


>
> Traceback (most recent call last):
> * File "<stdin>", line 1, in <module>
> ValueError: invalid literal for int() with base 10: '1e7'



Mick Krippendorf 11-08-2009 01:42 AM

Re: How convert string '1e7' to an integer?
 
Peng Yu wrote:
> It seems that int() does not convert '1e7'.

It seems it does, though:

>>> int('1e7', base=16)

487

Mick.

Gary Herron 11-08-2009 01:50 AM

Re: How convert string '1e7' to an integer?
 
Mensanator wrote:
> On Nov 7, 7:17 pm, Peng Yu <pengyu...@gmail.com> wrote:
>
>> It seems that int() does not convert '1e7'.
>>

>
> Because 'e' isn't a valid character in base 10.
>


But 1e7 is a valid float, so this works:

>>> int(float('1e7'))

10000000

That has a problem though, if you surpass the ability of a float:

>>> int(float('1e20'))

100000000000000000000L
>>> int(float('1e30'))

1000000000000000019884624838656L


Gary Herron



>
>> I'm wondering what
>> function to use to convert '1e7' to an integer?
>>
>>
>>>>> int('1e7')
>>>>>

>
>
>>>> int(1e7)
>>>>

> 10000000
>
>
>
>> Traceback (most recent call last):
>> File "<stdin>", line 1, in <module>
>> ValueError: invalid literal for int() with base 10: '1e7'
>>

>
>



Tim Chase 11-08-2009 02:05 AM

Re: How convert string '1e7' to an integer?
 
Mick Krippendorf wrote:
> Peng Yu wrote:
>> It seems that int() does not convert '1e7'.

> It seems it does, though:
>
>>>> int('1e7', base=16)

> 487


Bah...so narrow-minded ;-)

>>> print '\n'.join("Base %i: %i" % (base, int('1e7',

base=base)) for base in range(15,37))
Base 15: 442
Base 16: 487
Base 17: 534
Base 18: 583
Base 19: 634
Base 20: 687
Base 21: 742
Base 22: 799
Base 23: 858
Base 24: 919
Base 25: 982
Base 26: 1047
Base 27: 1114
Base 28: 1183
Base 29: 1254
Base 30: 1327
Base 31: 1402
Base 32: 1479
Base 33: 1558
Base 34: 1639
Base 35: 1722
Base 36: 1807

I feel so dirty interpreting numbers in convenient ways...like an
accountant. ("whaddaya mean I can't file my tax-return in base
17?! There's nothing in the supporting documentation that
mentions such draconian restrictions!")

-tkc





Roel Schroeven 11-08-2009 09:37 AM

Re: How convert string '1e7' to an integer?
 
Gary Herron schreef:
> Mensanator wrote:
>> On Nov 7, 7:17 pm, Peng Yu <pengyu...@gmail.com> wrote:
>>
>>> It seems that int() does not convert '1e7'.
>>>

>> Because 'e' isn't a valid character in base 10.
>>

>
> But 1e7 is a valid float, so this works:
>
> >>> int(float('1e7'))

> 10000000
>
> That has a problem though, if you surpass the ability of a float:
>
> >>> int(float('1e20'))

> 100000000000000000000L
> >>> int(float('1e30'))

> 1000000000000000019884624838656L


If that is a concern, decimal can help:

>>> import decimal
>>> int(decimal.Decimal('1e30'))

1000000000000000000000000000000L

--
The saddest aspect of life right now is that science gathers knowledge
faster than society gathers wisdom.
-- Isaac Asimov

Roel Schroeven

Thomas 11-08-2009 12:40 PM

Re: How convert string '1e7' to an integer?
 
Just a curiosity, why does Python do this?

>>> l = [(base, int('1e7', base=base)) for base in range(15,37)]
>>> l

[(15, 442), (16, 487), (17, 534), (18, 583), (19, 634), (20, 687),
(21, 742), (22, 799), (23, 858), (24, 919), (25, 982), (26, 1047),
(27, 1114), (28, 1183), (29, 1254), (30, 1327), (31, 1402), (32,
1479), (33, 1558), (34, 1639), (35, 1722), (36, 1807)]
>>> l = ([base, int('1e7', base=base)] for base in range(15,37))
>>> l

<generator object at 0x027803A0>
>>>


Mick Krippendorf 11-08-2009 01:39 PM

Re: How convert string '1e7' to an integer?
 
Thomas wrote:
> Just a curiosity, why does Python do this?
>
>>>> [(base, int('1e7', base=base)) for base in range(15,37)]

> [(15, 442), (16, 487), (17, 534), (18, 583), (19, 634), (20, 687),
> (21, 742), (22, 799), (23, 858), (24, 919), (25, 982), (26, 1047),
> (27, 1114), (28, 1183), (29, 1254), (30, 1327), (31, 1402), (32,
> 1479), (33, 1558), (34, 1639), (35, 1722), (36, 1807)]
>>>> ([base, int('1e7', base=base)] for base in range(15,37))

> <generator object at 0x027803A0>

Because the former is a list comprehension, whereas the latter is a
generator expression.

Mick.


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