istr-python 0.0.2

istr is a module to use strings as if they were integers.

Introduction

The istr module has exactly one class: istr.

With this it is possible to interpret string as if they were integers.

This can be very handy for solving puzzles, but also for other purposes.

And it is a nice demonstration of extending a class (str) with extra and changed functionality.

Installation

Installing istr with pip is easy.

$ pip install istr-python

or when you want to upgrade,

$ pip install istr-python --upgrade

Alternatively, istr.py can be just copied into you current work directory from GitHub (https://github.com/salabim/istr).

No dependencies!

Usage

Just start with

from istr import istr

Now we can define some istrs:

four = istr("4")
five = istr("5")

Them we can do

x= four * five

, after which x is istr("20")

And now we can do

print(x == 20)
print(x == "20")

resulting in two times True. That's because istr instances are treated as int, although they are strings.

That means that we can also say

print(x < 30)
print(x >= "10")

again resulting in two times True.

In contrast to an ordinary string

print(four + five)

prints 9, as istr are treated as ints.

So, how can we concatenate istrs? Just use the or operator (|):

print(four | five)

will output 45.

And the result is again an istr.

That means that

(four | five) / 3

is istr("9").

In order to multiply a string in the usual sense, you cannot use 3 * four, as that will be 12.

We use the matrix multiplication operator (@) for this. So 3 @ four is 444.

Also allowed are

abs(four)
-four 

For the in operator a istr is treated as an ordinary string, although it is possible to use ints as well:

"34" in istr(1234)
34 in istr(1234)

On the left hand side an istr is always treated as a string:

istr(1234) in "01234566890ABCDEF"

Note that all calculations are strictly integer calculations. That means that if a float variale is ever produced it will be converted to an int. Also divisions are always floor divisions!

There's a special case for istr(""). This is a proper empty string, but also represents the value of 0. That is to allow for istr("").join(i for i in "01234)"

Sorting a list of istrs is based on the integer value, not the string. So

' '.join(sorted('1 3 2 4 5 6 11 7 9 8 10 12 0'.split()))

is

'0 1 10 11 2 3 4 5 6 7 8 9'

,whereas

' '.join(sorted(istr('1 3 2 4 5 6 11 7 9 8 10 12 0'.split())))

is

'0 1 2 3 4 5 6 7 8 9 10 11'

Additional methods

It is possible to test for even/odd