如何手动输入 append 到 pandas csv 文件？

Question

Code

import pandas as pd
import csv

my_dict = { 'Customer'    : [],
            'Product'     : []
            }

x = input("Customer:")
y = input("Product:")

my_dict['Customer'].append(x)
my_dict['Product'].append(y)



df = pd.DataFrame(my_dict)


df.to_csv('data.csv', encoding='utf-8', index= True)

Output

,Customer,Product
0,Customer 1,Product 1

Question

How can I append new row If I run the script again and input new values?

Example

If I run the script again and my input would be Customer 2 & Product 2 and add new index too. I want the output to look like this in csv file:

,Customer,Product
0,Customer 1,Product 1
1, Customer 2, Product 2

But at the moment, it is just overwriting it.

Answer 1

You want to append the data to the existing data so try to read in the file and append the data:

import pandas as pd
import csv

try: #tries to read in existing data.csv file
    df = pd.read_csv('data.csv', encoding='utf-8', index_col = 0)
except FileNotFoundError: #if no file exists yet, create an empty dataframe
    df = pd.DataFrame()


my_dict = { 'Customer'    : [],
            'Product'     : []
            }

x = input("Customer:")
y = input("Product:")

my_dict['Customer'].append(x)
my_dict['Product'].append(y)



df = df.append(pd.DataFrame(my_dict))


df.to_csv('data.csv', encoding='utf-8', index= True)