2891-MethodChaining.py

# 2891. Method Chaining
# DataFrame animals
# +-------------+--------+
# | Column Name | Type   |
# +-------------+--------+
# | name        | object |
# | species     | object |
# | age         | int    |
# | weight      | int    |
# +-------------+--------+
# Write a solution to list the names of animals that weigh strictly more than 100 kilograms.
# Return the animals sorted by weight in descending order.
# The result format is in the following example.

# Example 1:

# Input: 
# DataFrame animals:
# +----------+---------+-----+--------+
# | name     | species | age | weight |
# +----------+---------+-----+--------+
# | Tatiana  | Snake   | 98  | 464    |
# | Khaled   | Giraffe | 50  | 41     |
# | Alex     | Leopard | 6   | 328    |
# | Jonathan | Monkey  | 45  | 463    |
# | Stefan   | Bear    | 100 | 50     |
# | Tommy    | Panda   | 26  | 349    |
# +----------+---------+-----+--------+
# Output: 
# +----------+
# | name     |
# +----------+
# | Tatiana  |
# | Jonathan |
# | Tommy    |
# | Alex     |
# +----------+
# Explanation: 
# All animals weighing more than 100 should be included in the results table.
# Tatiana's weight is 464, Jonathan's weight is 463, Tommy's weight is 349, and Alex's weight is 328.
# The results should be sorted in descending order of weight.
 
# In Pandas, method chaining enables us to perform operations on a DataFrame without breaking up each operation into a separate line or creating multiple temporary variables. 
# Can you complete this task in just one line of code using method chaining?
import pandas as pd

def findHeavyAnimals(animals: pd.DataFrame) -> pd.DataFrame:
    return animals[animals["weight"] > 100].sort_values(by='weight',ascending=False)[["name"]]

if __name__ == "__main__":
    l = [
        ["Tatiana","Snake",98,464],
        ["Khaled","Giraffe",50,41],
        ["Alex","Leopard",6,328],
        ["Jonathan","Monkey",45,463],
        ["Stefan","Bear",100,50],
        ["Tommy","Panda",26,349],
    ]
    print(findHeavyAnimals(pd.DataFrame(l,columns=["name","species","age","weight"])))