CODEWITHSUNDEEP
pythoncsv
Valer Ghazaryan
Valer Ghazaryan

Reputation: 35

How to find the five largest values of column in a csv file

My goal is to find the five most expensive laptops from a CSV file with details about the laptops and print the manufacturer, model name, and price of each.

In the screenshot, you can see the csv file

I was able to find the most expensive, however, I am having trouble finding the top 5.

import csv



class Laptops():
    def __init__(self, manufacturer, model_name, category, screen_size, screen, cpu, ram,storage,gpu,os,weight, price, os_version=None):
        self.manufacturer=manufacturer
        self.model_name=model_name
        self.category=category
        self.screen_size=screen_size
        self.screen=screen
        self.cpu=cpu
        self.ram=ram
        self.storage=storage
        self.gpu=gpu
        self.os=os
        self.weight=weight
        self.price=price
        self.os_version=os_version
        


def laptop():
    with open("PATH TO FILE,) as f:
        reader=csv.reader(f)

        for i, row in enumerate(reader):
            if i==0:
                continue
            else:
                yield(Laptops(
                    row[0],
                    row[1],
                    row[2],
                    float(row[3][:-1]),
                    row[4],
                    row[5],
                    row[6],
                    row[7],
                    row[8],
                    row[9],
                    row[11],
                    float(row[12].replace(",",".")),
                    row[10]
            ))



def five_expensive():

    most_expensive=None
    object_of_max_price=None
    for char in laptop():
        if most_expensive:
                if char.price>most_expensive:
                    most_expensive=char.price
                    object_of_max_price=char
        else:
            most_expensive=char.price
    return f"The most expensive notebook is {object_of_max_price.manufacturer} {object_of_max_price.model_name} with price of  {object_of_max_price.price} Euros "

Upvotes: 0

Views: 493

Answers (2)

Booboo
Booboo

Reputation: 44148

More efficient than sorting would be to use a heap queue:

import heapq:

for laptop in heapq.nlargest(5, laptop(), lambda x: x.price):
     print(laptop)

Or if you just want a list:

laptops = heapq.nlargest(5, laptop(), lambda x: x.price)

Note: If you want the N largest where N is a large number, then you would probably be better of sorting. If N is 1, then you could optimize this with just using the max function.

Upvotes: 0

rhorwitz
rhorwitz

Reputation: 104

I would recommend sorting the laptops by price and then returning the first 5. So something along the lines of:

laptops = laptop()
laptops.sort(key=lambda laptop: laptop.price, reverse=True)
return laptops[:5]

Upvotes: 3

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