In order to easily store the information of the song, we have created and used the following classes.
class Song:
"""The class to store the details of each song"""
attsToStore=('Name', 'Artist', 'Album', 'Genre', 'Location')
def __init__(self):
for att in self.attsToStore:
exec 'self.%s=None'%(att.lower()) in locals()
def setDetail(self, key, val):
if key in self.attsToStore:
exec 'self.%s=val'%(key.lower()) in locals()
It seems to me that the above method is much more scalable than the if/else syntax, but the way you use eval is not good and it is known as a less secure method. Please tell me why and how to define the above class in a better way.
python eval
First of all, eval is a bad programming habit as you said. To give you a couple of reasons:
For the above class, setattr can be used instead:
class Song:
"""The class to store the details of each song"""
attsToStore=('Name', 'Artist', 'Album', 'Genre', 'Location')
def __init__(self):
for att in self.attsToStore:
setattr(self, att.lower(), None)
def setDetail(self, key, val):
if key in self.attsToStore:
setattr(self, key.lower(), val)
Of course, there are cases where you have to use eval or exec, but those cases are very rare. It's definitely not a good habit to use eval in this case. The reason why we keep emphasizing that it's such a bad habit is that eval and exec are often used in the wrong way.
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