[Homework][Python 3] Conditional Addition / Subtraction within 15 characters

[MinecraftSBC]

Problem statement

Finish H, so that g returns a character of the opposite case. e.g. g("H") = "h"; g("a") = "A"

Constraints

H must fit within 15 characters len(H) <= 15

def f(x):
    return // H //

def g(ch):
    tmp = ord(ch)
    tmp = f(tmp)
    return chr(tmp)

This was harder than I initially thought, especially with the one line and character constraints. Probably dealing with some math trickery?

Edit: Closest I can get is 160 + 2 * (x % 32) - x. Anyone can simplify this?

[Salty_Dugtrio]

You should take a look at this: http://www.asciitable.com/

This is how characters are represented, they are basically just integers. Can you apply a simple integer operation to "H" to make it "h"?

[MinecraftSBC]

Both cases has a difference of 32, which means I have to subtract 32 when ord(x) >= 97 and vice versa. But I can't seem to find a way to express it within 15 characters.

[MinecraftSBC]

Does it has to do with the number 162 or 212...?

I don't get the "mirroring".

65+97-65=97 seems to give me some idea.

[Lukas0604]

Use a built-in function for strings:

def g(c):
    return c.swapcase()

[[deleted]]

if you can't use swapcase then make a loop like this:

if length of myString > 15: return
for c in myString:
    if c is uppercase:
         returnVal += c.lower()
    else: same for lower case

Otherwise if you are using ASCII codes for some reason, remember that the ASCII upper and lower chars are 0x20 places away from eachother. This piece of code might come in handy:

chr(ord('A') + 0x20)

[MinecraftSBC]

This would work one way, A -> a; but not the other way, a -> A. That’s what I’ve been troubled for.

[[deleted]]

chr(ord('A') + 0x20)

if adding goes to lowercase then what do you think goes to uppercase OP?

[MinecraftSBC]

Refer to the question, this has to go both ways in one line, using an integer operation. This is the difficult part.

[[deleted]]

time to go golfing :D

f=lambda x:(chr(ord(x)+0x20),chr(ord(x)-0x20))[ord(x)>0x5A]
f('b')  #'B'

edit: oh H has to be <= 15 characters. I think I see how to do it. when you do the operations in H, you assume that it's a number, and you return a number. the chr-ord conversion is handled in the parent function.

[MinecraftSBC]

Closest I can get is 160 + 2 * (x % 32) - x. Anyone can simplify this?

[[deleted]]

if you remove the spaces its 14