Question

Write a function in python that will take in a df (dataframe) and n (integer that determines the number of rows that the returned df will display):

create a new dataframe df1 by copying the input df, with only two columns "fruit" and "price" from the original df. Then add two new columns to df1 labeled "brand" and "time of purchase" and assign values appropriately.

Return df1

NOTE: If n= -1, return all the rows. If n ≥ 0 return df1 with n rows

Answer 1

Code:

def function1(df,n):    #this function in used for returning number of rows in argument 2
    if n==-1:            #if n is -1 then returned df as it is
        return df
    else:
        return df[:n]    #otherwise return dataframe with n rows using slicing like that

def function2(df):        #this function is used for copying one data frame to another with only 2 columns 
    df1=df[['fruit','price']]     #that copy fruit and price column with data from df to df1
    df1['brand']=['Fruits']*len(df)       #that insert new column brand in df1 with value of all rows if Fruits
    df1['time of purchase']=['4:00']*len(df)     #that insert new column time of purchase with value 4:00 in all rows
    return df1 

import pandas as pd 

# intialise data with fruit,price and quantity column 
data = {'fruit':['Apple', 'Banana', 'Orange', 'Grapes'], 'price':[20, 21, 19, 18],'Quantiry':[2, 10, 6, 9]} 
  
# Create DataFrame 
df = pd.DataFrame(data) 
function1(df,2)    #that will return dataframe with 2 rows
function2(df)       #that will return dataframe with 4 columns fruit,price and 2 new column brand time of purchase

#this function in used for returning number of rows in argument 2 #if n is -1 then returned df as it is def function1(df,n): if n=--1: return df else: return df[:n] #otherwise return dataframe with n rows using slicing like that def function(df): #this function is used for copying one data frame to another with only 2 columns df1=df[['fruit', 'price']] #that copy fruit and price column with data from df to dfi df1['brand']=['Fruits']*len(df) #that insert new column brand in dfi with value of all rows if Fruits df1['time of purchase']=['4:00']*len(df) #that insert new column time of purchase with value 4:00 in all rows return df1 import pandas as pd # intialise data with fruit, price and quantity column data = {'fruit': [ 'Apple', 'Banana', 'Orange', 'Grapes'], 'price': [20, 21, 19, 18], 'Quantiry':[2, 10, 6, 9]} # Create DataFrame df = pd. DataFrame (data) functioni(df, 2) #that will return dataframe with 2 rows function(df) #that will return dataframe with 4 columns fruit, price and 2 new column brand time of purchase

OUTPUT

for function1:

fruit price Quantiry 0 Apple 20 2 1 Banana 21 10

for function2:

fruit price brand time of purchase 0 Apple 20 Fruits 4:00 1 Banana 21 Fruits 4:00 2 Orange 19 Fruits 4:00 3 Grapes 18 Fruits 4:00