Is there a way to subtract 3 from every digit of a number?

[Avi Gross]

Ah, that is an interesting, Mike,  but not an informative answer. My
question is where the specific problem came from.  Yes, someone used to R
and coming to Python might work at adjusting to what is different and how to
get things done. I do that all the time as one hobby is learning lots of
languages and assessing them against each other.

So care to share your solution in R which I would assume you could do
easily?

My quick and dirty attempt, of no interest to the python community, using
the R form of integer that has a maximum, and the pipe operator that will
not be in standard R for another iteration, is this:

## R code using pipes to convert an integer
## to another integer by subtracting 3
## from each digit and wrapping around from
## 2 to 9 and so on, meaning modulo 10

## Load libraries to be used
library(dplyr)

## define function to return subtraction by N mod 10
rotdown <- function(dig, by=3) (dig -by) %% 10

start <- 123456789L

## Using pipes that send output between operators

start %>%
  as.character %>%
  strsplit(split="") %>%
  unlist %>%
  as.integer %>%
  rotdown %>%
  as.character %>%
  paste(collapse="") %>%
  as.integer

When run:

  > start %>%
  +   as.character %>%
  +   strsplit(split="") %>%
  +   unlist %>%
  +   as.integer %>%
  +   rotdown %>%
  +   as.character %>%
  +   paste(collapse="") %>%
  +   as.integer
[1] 890123456

The above is not meant to be efficient and I could do better if I take more
than a few minutes but is straightforward and uses the vectorized approach
so no obvious loops are needed.






-----Original Message-----
From: Python-list <python-list-bounces+avigross=verizon.net at python.org> On
Behalf Of C W
Sent: Sunday, February 21, 2021 9:48 AM
To: Chris Angelico <rosuav at gmail.com>
Cc: Python <python-list at python.org>
Subject: Re: Is there a way to subtract 3 from every digit of a number?

Hey Avi,

I am a long time R user now using Python. So, this is my attempt to master
the language.

The problem for me is that I often have an idea about how things are done in
R, but not sure to what functions are available in Python.

I hope that clears up some confusion.

Cheer!

On Sun, Feb 21, 2021 at 9:44 AM Chris Angelico <rosuav at gmail.com> wrote:

> On Mon, Feb 22, 2021 at 1:39 AM Avi Gross via Python-list 
> <python-list at python.org> wrote:
> > But you just moved the goalpost by talking about using a data.frame 
> > as
> that
> > (and I assume numpy and pandas) are not very basic Python.
>
> Given that the original post mentioned a pd.Series, I don't know how 
> far the goalposts actually moved :)
>
> ChrisA
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> https://mail.python.org/mailman/listinfo/python-list
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