how to extract digits from a float in python

Question

I have a floating point variable ie

123.456

how can I extract 12 ?

Answer 1

If you render the float as a string, then you can just index the digits you like:

str(123.456)[:2]

"proof" in shell:

>>> str(123.456)[:2]
'12'
>>>

Answer 2

If you want to do it a "mathy" way, you could also divide by 1e<number of digits to strip>. For example:

>>> int(123.456 / 1e1) # 1e1 == 10
12
>>> int(123.456 / 1e2) # 1e2 == 100
1
>>> int(123.456 / 1e-1) # 1e-1 == 0.1
1234

This will be much faster than converting float -> string -> int, but will not always behave exactly the same way as the string method above (eg, int(1.2 / 1e1) will be 0 , not '1.' ).

Answer 3

• result as float:

123.456//10
# res: 12.0

• result as integer

int(123.456)//10
# res: 12

• res as string: you have to care about the position of . !

str(123.456)[:2]  
# res: "12"