How to Sort a List of Lists by a Specific Index of the Inner List

How to sort a list of lists by a specific index of the inner list?

This is a job for itemgetter

>>> from operator import itemgetter
>>> L=[[0, 1, 'f'], [4, 2, 't'], [9, 4, 'afsd']]
>>> sorted(L, key=itemgetter(2))
[[9, 4, 'afsd'], [0, 1, 'f'], [4, 2, 't']]

It is also possible to use a lambda function here, however the lambda function is slower in this simple case

How to order a list of lists based on number of elements within the inner list? - python

You can sort by the len of the [0] element of each sublist.

>>> sorted(a, key=lambda i: len(i[0]), reverse=True)
[[[5, 4, 3, 2], [6, 7, 8, 9]], [[5, 6, 7, 1], [9, 0, 3, 4]], [[1, 2, 3], [1, 2, 7]], [[2, 2], [0, 4]]]

Sorting List of List by inner list's index in Java? (Java Equivalent of Python's 'sorted()')

Since Java 8 there is method List::sort accepting a custom Comparator which can be built using Comparator.comparing.

So, the input list of lists may be concisely sorted as follows:

List<List<String>> data = Arrays.asList(
    Arrays.asList("Kelly", "3.0"),
    Arrays.asList("Mark", "1.0"),
    Arrays.asList("Jeff", "2.0")
);

// sorting by index 1
data.sort(Comparator.comparing(x -> x.get(1))); 
// [[Mark, 1.0], [Jeff, 2.0], [Kelly, 3.0]]

// sorting by index 1 in reverse order using Collections.reverseOrder
data.sort(Comparator.comparing(x -> x.get(1), Collections.reverseOrder()));
// [[Kelly, 3.0], [Jeff, 2.0], [Mark, 1.0]]

// sorting by index 0 in reverse order using Comparator.reversed()
// here type of object being compared needs to be specified
data.sort(Comparator.comparing((List<String> x) -> x.get(0)).reversed());
// [[Mark, 1.0], [Kelly, 3.0], [Jeff, 2.0]]

sort list of lists by specific index of inner list

Use a custom sort key, to convert the last element to an integer just when sorting:

sorted(l1, key=lambda l: int(l[2].rstrip(',')))

The key is used to produce the value on which to sort, for each element in the list. So the lambda function is called for each element, and the above code extracts the l[2] value, converting it to an integer. The str.rstrip() call removes the trailing comma first.

Demo:

>>> l1 = [['test', 'hello', '60,'], ['why', 'to', '500,'], ['my', 'choice', '20,']]
>>> sorted(l1, key=lambda l: int(l[2].rstrip(',')))
[['my', 'choice', '20,'], ['test', 'hello', '60,'], ['why', 'to', '500,']]

How to sort a list of lists based on length of inner list?

Using sort or sorted with custom key.

Ex:

data = [['A', '1234', 'X'],['B', '12', 'X'],['C', '12345', 'X'],['D', '123', 'X']]
data.sort(key=lambda x: len(x[1]), reverse=True)

---

or sorted

data = sorted(data, key=lambda x: len(x[1]), reverse=True)

---

print(data)

Python- Sorting a list of lists by multiple indices, where inner lists may include None

Use sorted on your multidimensional list

l = [
  ['2016', 'E', None, '68', '94'],
  ['2016', 'A', None, '91', '25'],
  ['2016', 'C', None, '74', '25'],
  ['2017', 'C', None, '55', '20'],
  ['2015', 'D', None, '20', '14'],
  ['2016', 'B', None, '66', '66'],
  ['2017', 'E', None, '29', '41'],
  ['2017', 'F', None, '61', '22'],
  ['2015', 'A', None, '17', '96']
]
print(sorted(l))

prints

[['2015', 'A', None, '17', '96'], ['2015', 'D', None, '20', '14'], ['2016', 'A', None, '91', '25'], ['2016', 'B', None, '66', '66'], ['2016', 'C', None, '74', '25'], ['2016', 'E', None, '68', '94'], ['2017', 'C', None, '55', '20'], ['2017', 'E', None, '29', '41'], ['2017', 'F', None, '61', '22']]

Which is the same as your required output

Sort list of lists based on max value at a specific index in Python without the use of prebuilt functions or methods

In your code sample, you define food_list as a tuple while mentioning a list of list. In order to use list function like remove, copy or append, you need to add brackets around your lists.

Firstly, your food_list should be defined this way :

food_list = [
    ['banana', 10, 'f', 'yellow'],
    ['apple', 12, 'f', 'red'],
    ['pear', 60, 'f', 'green'],
    ['mango', 5, 'f', 'yellow'],
    ['lettuce', 3, 'v', 'green'],
    ['beans', 20, 'v', 'green'],
    ['red capsicum', 1, 'v', 'red'],
    ['corn', 20, 'v', 'yellow'],
]

Secondly you set up your minimum value before iterating over the list, you consider the 1st element of your list in order to start looking for a lower integer.

minValue = unsorted_food_list_copy[0]

Complete solution :

# initializing list
food_list = [
    ['banana', 10, 'f', 'yellow'],
    ['apple', 12, 'f', 'red'],
    ['pear', 60, 'f', 'green'],
    ['mango', 5, 'f', 'yellow'],
    ['lettuce', 3, 'v', 'green'],
    ['beans', 20, 'v', 'green'],
    ['red capsicum', 1, 'v', 'red'],
    ['corn', 20, 'v', 'yellow'],
]

unsorted_food_list_copy = food_list.copy()
sorted_food_list = []

for i in range(len(unsorted_food_list_copy)):
    minValue = unsorted_food_list_copy[0]
    for x in unsorted_food_list_copy:
        if x[1] < minValue[1]:
            minValue = x
    sorted_food_list.append(minValue)
    unsorted_food_list_copy.remove(minValue)

sorted_food_list_descending = sorted_food_list[::-1]
print(sorted_food_list_descending)

# Ouput
    [['pear', 60, 'f', 'green'],
    ['corn', 20, 'v', 'yellow'],
    ['beans', 20, 'v', 'green'],
    ['apple', 12, 'f', 'red'],
    ['banana', 10, 'f', 'yellow'],
    ['mango', 5, 'f', 'yellow'],
    ['lettuce', 3, 'v', 'green'],
    ['red capsicum', 1, 'v', 'red']]

---

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