CODEWITHSUNDEEP
pythonpython-3.xcsv
Alan
Alan

Reputation: 1

CSV reader/writer will not update .csv with new information, Python3

My working Python script (throws no errors) ignores the if statement, it seems, moving straight to the else statement. It does not seem to check my csv for a specific element, nor does it write that element to a new csv.

Must be a naive coding mistake?

The code used to be more complicated, but I have since stripped it down to discover this crux of the problem. No errors are being thrown, and the code executes completely. No errors means I can't exactly search for something specific.

import csv

    # Print merchant's inventory
    with open('merchant.csv', 'r') as csvfile:
        inventory = csv.reader(csvfile)
        for row in inventory:
            print(', '.join(row))

        choice = input('\n\nWhat would you like to purchase?\n\n')

        # Check to see if entry is actually in the printed list
        if choice in inventory:

            # Write choice into user.csv
            with open('user.csv', 'a') as A:
                inventory = csv.writer(A, delimiter = ',')
                inventory.writerow([choice])

        else:
            print("That's not in my list.")




 merchant.csv

ITEM    PRICE   WEIGHT
----------------------
Item1   20  14
Item2   15  15
Item3   100 1
----------------------

The code imitates a merchant trade of sorts, displaying a list of inventory (merchant.csv) and letting the user choose an item from that list, adding it to their inventory (user.csv), which begins empty.

user.csv remains empty through execution of main code.

Newbie here! Thanks for the help.

Upvotes: 0

Views: 54

Answers (2)

William Wade
William Wade

Reputation: 405

Alternative version to above using pandas
Skymons answer creates a list which is then searched by the user choice.
Whereas by reading the csv in as a DataFrame from the start the column can already be read as a list.

import csv
import pandas as pd

inv=pd.read_csv("merchant.csv")

choice = input('What would you like to purchase?\n')

if inv['Item'].str.contains(choice).any():
    with open('user.csv', 'a') as A:
            inventory = csv.writer(A, delimiter = ',')
            inventory.writerow([choice])

else:
    print("That's not in my list.")

Upvotes: 0

skymon
skymon

Reputation: 870

This should work:

import csv

# Print merchant's inventory
with open('merchant.csv', 'r') as csvfile:
    inventory = csv.reader(csvfile)
    items = []
    for row in inventory:
        items.append(row[0])
        print(', '.join(row))

    choice = input('\n\nWhat would you like to purchase?\n\n')

    # Check to see if entry is actually in the printed list
    if choice in items:

        # Write choice into user.csv
        with open('user.csv', 'a') as A:
            inventory = csv.writer(A, delimiter = ',')
            inventory.writerow([choice])

    else:
        print("That's not in my list.")

Upvotes: 1

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