On Sun, Feb 3, 2019 at 11:51 AM Sayth Renshaw <flebber.c...@gmail.com> wrote:
>
> Hi
>
> I am trying to convert a switch statement from C into Python. (why?
> practising).
>
> This is the C code.
>
> printf("Dated this %d", day);
> switch (day) {
> case 1: case 21: case 31:
> printf("st"); break;
> case 2: case 22:
> printf("nd"); break;
> case 3: case 23:
> printf("rd"); break;
> default: printf("th"); break;
>
> }
> printf(" day of ");
>
> #Premise if the use enter an int as the date 21 for example it would print
> 21st. It appends the correct suffix onto a date.
>
> Reading and trying to implement a function that uses a dictionary. Not sure
> how to supply list into it to keep it brief and with default case of 'th'.
>
> This is my current code.
>
> def f(x):
> return {
> [1, 21, 31]: "st",
> [2, 22]: "nd",
> [3, 23]: "rd",
> }.get(x, "th")
>
>
> print(f(21))
>
> I have an unhashable type list. Whats the best way to go?
What you really want there is for 1 to map to "st", and 21 to
separately map to "st", not for some combined key [1, 21, 31] to map
to "st". There's no easy syntax for this, and maybe a helper function
would, well, help.
def mapper(*plans):
plans = iter(plans)
d = {}
while "moar plans":
try: keys = next(plans)
except StopIteration: return d
value = next(plans)
for key in keys: d[key] = value
def f(x):
return mapper(
[1, 21, 31], "st",
[2, 22], "nd",
[3, 23], "rd",
).get(x, "th")
Of course, you can also precompute this:
day_ordinal = mapper(
[1, 21, 31], "st",
[2, 22], "nd",
[3, 23], "rd",
)
def f(x): return day_ordinal.get(x, "th")
ChrisA
--
https://mail.python.org/mailman/listinfo/python-list
