Arrange list of strings that are divided into 4 parts by the different parts?

Question

I have a list comprised of strings that all follow the same format 'Name%Department%Age'

I would like to order the list by age, then name, then department.

alist = ['John%Maths%30', 'Sarah%English%50', 'John%English%30', 'John%English%31', 'George%Maths%30'] 

after sorting would output:

['Sarah%English%50, 'John%English%31', 'George%Maths%30', 'John%English%30, 'John%Maths%30']

The closest I have found to what I want is the following (found here: How to sort a list by Number then Letter in python? )

import re

def sorter(s):

     match = re.search('([a-zA-Z]*)(\d+)', s)

     return int(match.group(2)), match.group(1)


sorted(alist, key=sorter)

Out[13]: ['1', 'A1', '2', '3', '12', 'A12', 'B12', '17', 'A17', '25', '29', '122']  

This however only sorted my layout of input by straight alphabetical.

Any help appreciated,

Thanks.

Answer 1

You are on the right track.

Personally, I:

• would first use string.split() to chop the string up into its constituent parts;
• would then make the sort key produce a tuple that reflects the desired sort order.

For example:

def key(name_dept_age):
  name, dept, age = name_dept_age.split('%')
  return -int(age), name, dept

alist = ['John%Maths%30', 'Sarah%English%50', 'John%English%30', 'John%English%31', 'George%Maths%30']

print(sorted(alist, key=key))

Answer 2

Use name, department, age = item.split('%') on each item.

Make a dict out of them {'name': name, 'department': department, 'age': age}

Then sort them using this code https://stackoverflow.com/a/1144405/277267

sorted_items = multikeysort(items, ['-age', 'name', 'department'])

Experiment once with that multikeysort function, you will see that it will come in handy in a couple of situations in your programming career.