如何根据excel的另一列值对列求和

Question

I would like to ask how to sum using python or excel. Like to do summation of "number" columns based on "time" column. Sum of the Duration for (00:00 am - 00:59 am) is (2+4) 6. Sum of the Duration for (02:00 am - 02:59 am) is (3+1) 4. Could you please advise how to ?

Answer 1

When you have a dataframe you can use groupby to accomplish this:

# import pandas module
import pandas as pd
# Create a dictionary with the values
data = {
    'time' : ["12:20:51", "12:40:51", "2:26:35", "2:37:35"],
    'number' : [2, 4, 3, 1]}

# create a Pandas dataframe
df = pd.DataFrame(data)
# or load the CSV
df = pd.read_csv('path/dir/filename.csv')
# Convert time column to datetime data type
df['time'] =  df['time'].apply(pd.to_datetime, format='%H:%M:%S')
# add values by hour
dff = df.groupby(df['time'].dt.hour)['number'].sum()
print(dff.head(50))

output:

time
12    6
2     4

When you need more than one column. You can pass the columns as a list inside .groupby(). The code will look like this:

import pandas as pd
df = pd.read_csv('filename.csv')
# Convert time column to datetime data type
df['time'] = df['time'].apply(pd.to_datetime, format='%H:%M:%S')
df['date'] = df['date'].apply(pd.to_datetime, format='%d/%m/%Y')
# add values by hour
dff = df.groupby([df['date'], df['time'].dt.hour])['number'].sum()
print(dff.head(50))
# save the file
dff.to_csv("filename.csv")