I would like to take a data from in the csv file-CodePudding

this is the equivalent of my csv file;

customer,quantity
a,250
a,166
c,354
b,185
a,58
d,68
c,263
c,254
d,320
b,176
d,127
...

this csv file has 8000 data. I want to separate the "a", "b", ,"c", ... "z" in the customer column with the quantity column. this csv file is just an example, actually customers are too many. I don't know the customer names. what i want is for each client to have their own csv file. and I have to do them using python.

I'm sorry for my bad english.

CodePudding user response：

I am not good in the pandas module but I get what you want this code makes the .csv of the user name and the inserts his/her name and quantity in the file. You can try this if you get any errors then please let me know in the comment. Note: Please try this with a copy of the same data file

# pip install pandas
import pandas as pd

data = pd.read_csv('abc.csv') # write you csv file name here.

all_customer_value = list(data['customer'])
all_customer_quantity = list(data['quantity'])
all_customer_name = set(data['customer'])

for user in all_customer_name:
    with open(f'{user}.csv','w')as file:
        file.write('customer,quantity\n') # edited

for index,value in  enumerate(all_customer_value):
    with open(f'{value}.csv','a') as file:
        file.write(f'{value}, {all_customer_quantity[index]}\n')

CodePudding user response：

I believe the simplest way is using a dict to store the customer name and all related quantities:

with open('the_file.csv', 'r') as file_in:
    csv_in = reader(file_in)
    customers = {}
    first_line = True
    for cust, qty in csv_in:
        if first_line:
            first_line = False
            continue
        if cust not in customers:
            customers[cust] = [qty]
        else:
            customers[cust].append(qty)
    for cust in customers:
        with open(f'{cust}.csv', 'w', newline='') as file_out:
            csv_out = writer(file_out)
            for qty in customers[cust]:
                csv_out.writerow([cust, qty])

CodePudding user response：

If you're okay with Pandas (replace file.csv with your input filename):

import pandas as pd

for customer, df in pd.read_csv("file.csv").groupby("customer"):
    df.to_csv(f"{customer}.csv", index=False)

If you want to do more or less the same without Pandas:

import csv
from operator import itemgetter
from itertools import groupby

with open("file.csv", "r") as file:
    data = list(csv.reader(file))
header, data = data[0], data[1:]
key = itemgetter(0)
for customer, group in groupby(sorted(data, key=key), key=key):
    with open(f"{customer}.csv", "w") as file:
        writer = csv.writer(file)
        writer.writerow(header)
        writer.writerows(group)

If you want to avoid the sorting, then a solution like the one from @gimix might be better.