Question

how to calculate the sum of the particular value of column in data frame in python.

eg:

this is an excel file loaded into a dataframe.   

Cloth type	Size	Quantity	Color
Shirt	Small	2	Red
Jacket	X-large	5	Grey
Pantsuit	Medium	1	Green
Shirt	Medium	10	Blue
Shirt	Small	5	Green
Cardigan	Large	3	White
Pantsuit	Small	2	Pink
Cardigan	Large	6	Red
Jacket	Medium	4	Blue

a. How to create a dataframe with 2 columns: cloth type, Total quantity of that cloth (sum)?

eg: for the above record the output should be as follows:

Cloth type Quantity  

Shirt 17

Jacket 9

Pantsuit 3

Cardigan 9

Answer 1

df1=df.groupby(by="Cloth type").sum()
print(df1)

output -

            Quantity
Cloth type          
Cardigan           9
Jacket             9
Pantsuit           3
Shirt             17

Explanation :

We use groupby function to group dataframe by column = Cloth type and then we use sum() function to sum rest of the column values.Instead of sum() , you can even use other statistical functions like mean(),max(),min()