What is the SetDefault function in Python

Key Takeaways

the set default function for specific scenarios related to dictionaries Now set default Works similarly toget but it actually assigns a default value as well as returning that value to you if a key does not exist so have a look at this example here we have a student's grades dictionary now this is going to contain nested dictionaries so what we do is we attempt to get the math grades for Alice okay so we say student grades doget Alice and then we return a default value of a dictionary if the Alice doesn't exist in this case it doesn't exist so what happens is we return the dictionary we then look at that dictionary and we say math grades at math is equal to zero now the issue here is that we don't actually modify what exists inside of student grades we just modify what was returned as the default value because Alice didn't exist however when you use the set default method this is different what this does is actually assign the default value and then return that to you so you're referencing the same object that now exist inside of the dictionary so here when we say English grades is equal to student grades. set default what it does is check if the Alice Key exists if it does just Returns the value associated with it if it doesn't it assigns the key Alice equal to the default value dictionary then Returns the default value dictionary to us so we have the dictionary here we then say the dictionary at English is equal to 85 and now that actually modifies what exists inside of student grades so when I print that out I get the key value pair Alice and then the nested dictionary that we modified from the default value