sort key lambda python code example

Example 1: python lambda key sort

>>> student_tuples = [
...     ('john', 'A', 15),
...     ('jane', 'B', 12),
...     ('dave', 'B', 10),
... ]
>>> sorted(student_tuples, key=lambda student: student[2])   # sort by age
[('dave', 'B', 10), ('jane', 'B', 12), ('john', 'A', 15)]

Example 2: python sort based off lambda

a = sorted(a, key=lambda x: x.modified, reverse=True)

Example 3: python sort list in place

# Basic syntax:
your_list.sort()

# Example usage:
your_list = [42, 17, 23, 111]
your_list.sort()
print(your_list)
--> [17, 23, 42, 111]

# If you have a list of numbers that are of type string, you can do the
# following to sort them numerically without first converting to type 
# int. E.g.:
your_list = ['42', '17', '23', '111']
your_list.sort(key=int)
print(your_list)
--> ['17', '23', '42', '111']

# If you want to sort a list of strings in place based on a number 
# that is consistently located at some position in the strings, use
# a lambda function. E.g.:
your_list =['cmd1','cmd10', 'cmd111', 'cmd50', 'cmd99']
your_list.sort(key=lambda x: int(x[3:]))
print(your_list)
--> ['cmd1', 'cmd10', 'cmd50', 'cmd99', 'cmd111']

# If you don't want to sort the list in place, used sorted. E.g.:
your_list = [42, 17, 23, 111]
your_list_sorted = sorted(your_list)
print(your_list_sorted)
--> [17, 23, 42, 111]

Example 4: python sort list with lambda key

#return new list
>>> student_tuples = [
...     ('john', 'A', 15),
...     ('jane', 'B', 12),
...     ('dave', 'B', 10),
... ]
>>> sorted(student_tuples, key=lambda student: student[2])   # sort by age
[('dave', 'B', 10), ('jane', 'B', 12), ('john', 'A', 15)]

#sort in place
data = [("Apples", 5, "20"), ("Pears", 1, "5"), ("Oranges", 6, "10")]

data.sort(key=lambda x:x[0])
print(data)
OUTPUT
[('Apples', 5, '20'), ('Oranges', 6, '10'), ('Pears', 1, '5')]

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