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return in a function - Skaperen - Mar-06-2021
suppose i have a bunch of code like
if first_name == 'alex':
return 1
if middle_name == 'larry':
return 2
if middle_name == 'mark':
return 3
if first_name == 'sarah':
return 4
if surname == 'smith':
return 5duplicated in several places and i want to reduce the duplication by putting it in a function. how would i do that?
RE: return in a function - michael1789 - Mar-06-2021
Python dictionary.
dict = {'alex' : 1,
'larry' : 2,
'mark' : 3}
print(dict['mark'])
RE: return in a function - snippsat - Mar-06-2021
Dictionary as mention bye michael1789,but don't use
dict as Python use that name.Can throw in in
get to handle missing key,and give a familiar name of what is called other languages.def switch_case(record, search):
return record.get(search, f'<{search}> not in record')
if __name__ == '__main__':
record = {
'alex': 1,
'larry': 2,
'mark': 3
}
search = 'mark'
print(switch_case(record, search))Need or not,so to we get switch case version in Python 3.10.Called Structural Pattern Matching which is more powerful that just simple switch case.
RE: return in a function - ndc85430 - Mar-06-2021
Nice. I didn't realise 3.10 had pattern matching.
RE: return in a function - Skaperen - Mar-06-2021
(Mar-06-2021, 05:13 AM)michael1789 Wrote: Python dictionary.
dict = {'alex' : 1, 'larry' : 2, 'mark' : 3} print(dict['mark'])
the example i gave involves testing various different variables. maybe it's a bad example. the "bunch of code" can't be changed. the question is about how to have function A call function B and have function B effect the return all the way to the caller of function A. put the "bunch of code" inside function B so function A can just call function B in all those places it had that "bunch of code". but what about those returns? can function B do a return for function A? not really. see the complication?
RE: return in a function - Gribouillis - Mar-07-2021
Function A could just call
def A():
...
return B()
RE: return in a function - Skaperen - Mar-07-2021
what if the "bunch of code" only returns in some cases and "falls through" in others?
RE: return in a function - Gribouillis - Mar-08-2021
You could do like
list.index()def A():
try:
return B(value)
except ValueError:
pass
RE: return in a function - Skaperen - Mar-08-2021
so do i get to put the duplicated and complicated decision making code in a function? i'm guessing B() should raise an exception. then A() gets the exception or A()'s caller does.
RE: return in a function - nilamo - Mar-11-2021
I would use a sentinel value (None, if that's not valid) to mark a Not Found case. So for this:
def lookup(first_name, middle_name, surname):
if first_name == 'alex':
return 1
if middle_name == 'larry':
return 2
if middle_name == 'mark':
return 3
if first_name == 'sarah':
return 4
if surname == 'smith':
return 5
return None
if (res := lookup(f, m, s)) is None:
# not found