Get part of an integer in Python

Question

Is there an elegant way (maybe in numpy) to get a given part of a Python integer, eg say I want to get 90 from 1990.

I can do:

my_integer = 1990
int(str(my_integer)[2:4])
# 90

But it is quite ugly.

Any other option?

Answer 1

1990 % 100 would do the trick.

(% is the modulo operator and returns the remainder of the division, here 1990 = 19*100 + 90.)

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Added after answer was accepted:

If you need something generic, try this:

def GetIntegerSlice(i, n, m):
  # return nth to mth digit of i (as int)
  l = math.floor(math.log10(i)) + 1
  return i / int(pow(10, l - m)) % int(pow(10, m - n + 1))

It will return the nth to mth digit of i (as int), i.e.

>>> GetIntegerSlice(123456, 3, 4)
34

Not sure it's an improvement over your suggestion, but it does not rely on string operations and was fun to write.

(Note: casting to int before doing the division (rather than only casting the result to int in the end) makes it work also for long integers.)

Answer 2

Here is generic function for getting any number of last digits:

In [160]: def get_last_digits(num, digits=2):
   .....:         return num%10**digits
   .....:

In [161]: get_last_digits(1999)
Out[161]: 99

In [162]: get_last_digits(1999,3)
Out[162]: 999

In [166]: get_last_digits(1999,10)
Out[166]: 1999