Can someone explain me a few things about python?

Question

So if there is a code like this:

for c in char:
char += 1

Or something. I don't usually see the "c" defined anywhere. And neither do I see the "char" being defined. Why?

Same thing with functions:

def random_func(func, arg)
xxxx xxx yyyyyy

The "func" and "arg" are never defined. So what are they and how do they magically work? Am I missing something here? If I even try to use undefined variables, oh boy does the system remind me. But in Sololearn's examples, this never happens.

Answer 1

for c in char:
char += 1

You ask you program to put every value of "char" variable into "c". 1 by 1 with each loop run. "c" exists only when the loop is running. "char" should be defined before this loop.

def random_func(func, arg):
pass

"func, arg" aren't variables. Treat them as a placeholder for everything you put in a function.
For example:
def add(first, second):
return first + second

print(add(15, 20))

Output: 35.
"first" is 15 and "second" is 20 in this example.

Answer 2

For simplification, you can see loop variables and function parameters as just another style of assigning.

See 'for c in chars' as 'Please do c = letter for every letter in chars'.

(You can test it: After the loop is over, the variable still has the last value.)

See a function definition like 'def f(x)' as meaning: 'Whenever I call the function f, please do x = the argument I pass'.