How do I sort a list in ascending order using a specific column, without using a build in function? (Python)

Question

I have imported a CSV file to a list in python containing animal data with the following columns:

Sanctuary Identification,Type,Breed,Vaccinated,Neutered

P23533,Cat,Persian,Yes,Yes

P43533,Dog,Poodle,Yes,No

P18754,Dog...

The data appears in the following format:

[[P23533,Cat,Persian,Yes,Yes],[P43533,Dog,Poodle,Yes,No],[P18754,Dog...]]

I would like to sort the list in ascending order of their Sanctuary Indentifaction, ie:

P1111, Cat, ..
P2222 Dog, ..
P3333.. etc

I cannot use any build in libraries, can anyone suggest how I might go about this?

Answer 1

You could sort the nested list using sorted built-in function, then pass in the first column as the key to be sorted. Below is the example.

In [1]: my_list = [["P23533","Cat","Persian","Yes","Yes"],["P43533","Dog","Poodle","Yes","No"], ["P1111","Asd","Test","
   ...: Yes","Yes"]]

In [2]: sorted(my_list, key=lambda x: x[0])
Out[2]:
[['P1111', 'Asd', 'Test', 'Yes', 'Yes'],
 ['P23533', 'Cat', 'Persian', 'Yes', 'Yes'],
 ['P43533', 'Dog', 'Poodle', 'Yes', 'No']]

Alternatively, you can use pandas.read_csv to load your csv into DataFrame object, then use sort_values function:

In [10]: df.sort_values(["SanctuaryID"]).reset_index(drop=True)
Out[10]:
  SanctuaryID Animal     Type Col4 Col5
0       P1111    Asd     Test  Yes  Yes
1      P23533    Cat  Persian  Yes  Yes
2      P43533    Dog   Poodle  Yes   No