CODEWITHSUNDEEP
pythontry-catch
Wayne Treible
Wayne Treible

Reputation: 153

Multiple Try/Except blocks

I have multiple try/except blocks in a program where I am analyzing a dictionary input from another module. I basically use the try/except (EAFP) to check if a certain key is in the input (otherwise, I want to raise an error).

I was wondering if there is a more general approach. Instead of 

try:
    xyz = a['some_key']
except:
    print_error("Key 'some_key' was not defined")

dozens of times, if there was a way to do something like

try:
    xyz = a['some_key']
    xyz2 = a['some_key2']
    ...
except:
    print_error("The key(s) that were not included were some_key, some_key2")

Upvotes: 1

Views: 425

Answers (1)

NightShadeQueen
NightShadeQueen

Reputation: 3334

borked_keys = set()
for key in list_of_keys_needed:
    try:
       xyz = a[key]
    except KeyError:
       borked_keys.add(key)

#python3 variant
print("The following keys were missing:", ",".join(borked_keys))
#or, as suggested by jonrsharpe
if borked_keys: raise KeyError(",".join(str(i) for i in borked_keys))

#python 2 variant
print "The following keys were missing: " + ",".join(borked_keys)
#or 
if borked_keys: raise KeyError ",".join(str(i) for i in borked_keys)

#if the keys are already strings, you can just use ",".join(borked_keys).

Upvotes: 4

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