595. Big Countries

Description

Pandas Schema

data = [['Afghanistan', 'Asia', 652230, 25500100, 20343000000], ['Albania', 'Europe', 28748, 2831741, 12960000000], ['Algeria', 'Africa', 2381741, 37100000, 188681000000], ['Andorra', 'Europe', 468, 78115, 3712000000], ['Angola', 'Africa', 1246700, 20609294, 100990000000]]
world = pd.DataFrame(data, columns=['name', 'continent', 'area', 'population', 'gdp']).astype({'name':'object', 'continent':'object', 'area':'Int64', 'population':'Int64', 'gdp':'Int64'})

Table: World

+-------------+---------+
| Column Name | Type    |
+-------------+---------+
| name        | varchar |
| continent   | varchar |
| area        | int     |
| population  | int     |
| gdp         | bigint  |
+-------------+---------+
name is the primary key (column with unique values) for this table.
Each row of this table gives information about 
the name of a country, the continent to which it belongs,
its area, the population, and its GDP value.

A country is big if:

• it has an area of at least three million (i.e., 3000000 km²), or
• it has a population of at least twenty-five million (i.e., 25000000).

Write a solution to find the name, population, and area of the big countries.

Return the result table in any order.

The result format is in the following example.

Example 1:

• Input:

    World table:
    +-------------+-----------+---------+------------+--------------+
    | name        | continent | area    | population | gdp          |
    +-------------+-----------+---------+------------+--------------+
    | Afghanistan | Asia      | 652230  | 25500100   | 20343000000  |
    | Albania     | Europe    | 28748   | 2831741    | 12960000000  |
    | Algeria     | Africa    | 2381741 | 37100000   | 188681000000 |
    | Andorra     | Europe    | 468     | 78115      | 3712000000   |
    | Angola      | Africa    | 1246700 | 20609294   | 100990000000 |
    +-------------+-----------+---------+------------+--------------+
    

• Output:

    +-------------+------------+---------+
    | name        | population | area    |
    +-------------+------------+---------+
    | Afghanistan | 25500100   | 652230  |
    | Algeria     | 37100000   | 2381741 |
    +-------------+------------+---------+
    

Submitted Code

import pandas as pd

def big_countries(world: pd.DataFrame) -> pd.DataFrame:
    world = world[(world['area'] >= 3000000) | (world['population'] >= 25000000)]
    return world[['name', 'population', 'area']]

Runtime: 259 ms | Beats 76.60%
Memory: 68.82 MB | Beats 57.11%

조건에 맞는 행만 출력하는 간단한 문제다.

Other Solutions

1st

def big_countries(world: pd.DataFrame) -> pd.DataFrame:
    # select name, population, area from world where area>=3000000 or population>=25000000
    return world.loc[
        (world['area'] >= 3000000) | (world['population'] >= 25000000),
        ['name', 'population', 'area']
    ]

loc[]을 사용해도 된다.

2nd

SELECT name, population, area
FROM World
WHERE area >= 3000000 OR population >= 25000000;

OR 사용

select area,population,name
from world
where area>=3000000
union
select area,population,name
from world
where population>=25000000

UNION 사용