python String to number

Question

I'm trying to convert a string that contains a decimal number like this.

bet1size = "0.00000001"

I've tried

betsize = int(bet1size)

but that comes up with

Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ValueError: invalid literal for int() with base 10: '0.00000001'

I've also tried

betsize = float(bet1size)

but this comes up with 1e-08 and

betsize = Decimal(bet1size)

comes with with 1E-8

Why does it this happen and how can I do it properly?

what do you want as output? 0.00000001 is the same as 1e-08 aka 10^-8 — yoopoo
– yoopoo, Commented Jun 30, 2014 at 9:36
I want to convert it to a number so I can double it then I was going to convert it back to a string, but like this the string ends up being 2e-08 not 0.00000002 — user3789691
– user3789691, Commented Jun 30, 2014 at 9:40

Jakob · Accepted Answer · 2014-06-30 09:40:46Z

2

The scientific notation is just a convenient way of storing/printing a floating point number. When there are a lot of leading zeros as in your example, the scientific notation might be easier to read.

In order to print a specific number of digits after a decimal point, you can specify a format string with print:

format(float(bet1size), '.8f')

answered Jun 30, 2014 at 9:40

Jakob

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Comments

unwind · Accepted Answer · 2014-06-30 09:36:26Z

0

It's being done "properly" by float(). 1e-08 is "0.00000001".

It's just a matter of how you format it for printing, the number is the same.

answered Jun 30, 2014 at 9:36

unwind

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Comments

GuiTeK · Accepted Answer · 2014-06-30 09:38:19Z

0

int means integer. You can't store a decimal number in a int. For the two other, it means 1 * 10^-8, which equals to 0.00000001.

answered Jun 30, 2014 at 9:38

GuiTeK

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