## How to create a lambda function from a tuple of values

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The basic objective is to sort a list of lists based on a field in the inner lists. So i have the below Python code for doing it:

import sys def sort_cleaned_data(data, fields=None): if not isinstance(fields, tuple): raise ValueError("Argument to the function has to be a tuple") else: if all(list(map(lambda x:isinstance(x, int), fields))): sorted_data = sorted(data, key=lambda x:(x[2],x[1])) return sorted_data else: raise ValueError("All the values inside the fields tuple have to be integers") data = [ ["John", 34, 2], ["Ashley", 30, 2], ["Peter", 28, 5], ["Bill", 29, 5], ["Jennifer", 65, 4], ["Laura", 33, 3] ] try: sorted_data = sort_cleaned_data(data, fields=(2,1)) except ValueError as e: print(e) sys.exit(1) for d in sorted_data: print(d)

In the function sort_cleaned_data i have the fields tuple which contain the fields of the inner array on which to sort. So i have to dynamically generate the function : `key=lambda x:(x[2],x[1])`

based on the fields list.

I think this is the case of eval in Python but i am not sure how to do this . Can someone please help me here .

Many thanks in advance.

This is overly complicated. Just use `operator.itemgetter`

to create your key function.

import operator def sort_cleaned_data(data, fields=None): return sorted(data, key=operator.itemgetter(*fields)) data = [ ["John", 34, 2], ["Ashley", 30, 2], ["Peter", 28, 5], ["Bill", 29, 5], ["Jennifer", 65, 4], ["Laura", 33, 3] ] sorted_data = sort_cleaned_data(data, fields=(2,1)) for d in sorted_data: print(d)

Output:

['Ashley', 30, 2] ['John', 34, 2] ['Laura', 33, 3] ['Jennifer', 65, 4] ['Peter', 28, 5] ['Bill', 29, 5]

Hi there, I'm trying to create the most efficient way of sorting a tuple. here is that the lambda is receiving the two values from the sort function, Use the lambda declaration operator => to separate the lambda's parameter list from its body. To create a lambda expression, you specify input parameters (if any) on the left side of the lambda operator and an expression or a statement block on the other side. Any lambda expression can be converted to a delegate type.

Using a comprehension:

sorted(data, key=lambda x: tuple(x[i] for i in fields))

Now `fields`

can be arbitrary in size and values, provided `x`

(inner list) has enough elements to not raise IndexError.

I quick refresher of lists, tuples, and lambda function in python. You can create a duplicate list or join 2 lists. Here we are using nested iterations, wherein for each value in essaytext column which is already tokenized on Learn to create a Lambda function in Python, pass multiple arguments, return multiple values, combine with map() and filter(), sort iterables, nested lambdas, jump tables and many more.

You're making it much more complicated than it has to be:

def sort_cleaned_data(data, fields): return sorted(data, key=lambda x: (x[fields[0]], x[fields[1]])) data = [ ["John", 34, 2], ["Ashley", 30, 2], ["Peter", 28, 5], ["Bill", 29, 5], ["Jennifer", 65, 4], ["Laura", 33, 3] ] sorted_data = sort_cleaned_data(data, fields=(2,1)) for d in sorted_data: print(d)

Learn to create a Lambda function in Python, pass multiple arguments, return Return multiple values by packing them in a tuple findSquareCube = lambda Lambda for tuple sorting (python) # The values are coming into the function as tuples, what I've done is # instantly determine if there is a tie between them and reset the vaules # of a and b

The lambda operator or lambda function is a way to create small anonymous the function func applied on the corresponding element of the list or tuple "seq". A Python lambda function behaves like a normal function in regard to arguments. Therefore, a lambda parameter can be initialized with a default value: the parameter n takes the outer n as a default value. The Python lambda function could have been written as lambda x=n: print(x) and have the same result.

objects in sequences. This tutorial on Python map focuses on lists, tuples, sets and more! Let's breakdown each element: Function: map() will Note: lambda is a keyword for building anonymous functions. They help you Create Tuple With One Item. To create a tuple with only one item, you have to add a comma after the item, otherwise Python will not recognize it as a tuple.

Filtering a Sequence's Values with the Built-In filter Function value, you can use a lambda expression (or simply a lambda) to define the A lambda function that runs on each element of the list. It will return the product of that number as per the previous result. Print the result returned by the reduce function. Why (and why not) use lambda functions? As you will see in the next section, lambdas are treated the same as regular functions at the interpreter level.