Lambda function

it is a function that is anonymous in nature and one-line syntex. Implicit return of expression.

syntex

lambda params: expression

example

def multiply_by(multiplier):
    return lambda x: x * multiplier

multiply_by_3 = multiply_by(3)
print(multiply_by_3(5))
# 15

multiply_by_5 = multiply_by(5)
print(multiply_by_5(5))
# 25

sorting a list of dictionaries using lambda function

students = [
    {'name': 'Mamra', 'score': 50},
    {'name': 'Thundercat', 'score': 90},
    {'name': 'Tom', 'score': 20}
]

# sort by score in ascending order
students.sort(key=lambda student: student['score'])

print(students)
# [{'name': 'Tom','score': 20}, {'name': 'Mamra','score': 50}, {'name': 'Thundercat','score': 90}]

# sort by score in descending order
students.sort(key=lambda student: student['score'], reverse=True)
print(students)
# [{'name': 'Thundercat','score': 90}, {'name': 'Mamra','score': 50}, {'name': 'Tom','score': 20}]

filtering a list of dictionaries using lambda function

students = [
    {'name': 'Mamra', 'score': 50},
    {'name': 'Thundercat', 'score': 90},
    {'name': 'Tom', 'score': 20}
]

# filter students with score greater than 50
high_score_students = list(filter(lambda student: student['score'] > 50, students))
print(high_score_students)
# [{'name': 'Thundercat','score': 90}]