extracting row from CSV file with Python / Django

a56z 0
Viewed 26

hey I'm trying to extract certain row from a CSV file with content in this form:

POS,Transaction id,Product,Quantity,Customer,Date
1,E100,TV,1,Test Customer,2022-09-19
2,E100,Laptop,3,Test Customer,2022-09-20
3,E200,TV,1,Test Customer,2022-09-21
4,E300,Smartphone,2,Test Customer,2022-09-22
5,E300,Laptop,5,New Customer,2022-09-23
6,E300,TV,1,New Customer,2022-09-23
7,E400,TV,2,ABC,2022-09-24
8,E500,Smartwatch,4,ABC,2022-09-25

the code I wrote is the following

def csv_upload_view(request):
    print('file is being uploaded')

    if request.method == 'POST':
        csv_file = request.FILES.get('file')
        obj = CSV.objects.create(file_name=csv_file)

        with open(obj.file_name.path, 'r') as f:
            reader = csv.reader(f)
            reader.__next__()
            for  row in reader:
                data = "".join(row)
                data = data.split(";")
                #data.pop()
                print(data[0], type(data))
                transaction_id = data[0]
                product = data[1]
                quantity = int(data[2])
                customer = data[3]
                date = parse_date(data[4])

In the console then I get the following output:

Quit the server with CONTROL-C.
[22/Sep/2022 15:16:28] "GET /reports/from-file/ HTTP/1.1" 200 11719
file is being uploaded
1E100TV1Test Customer2022-09-19 <class 'list'>

So that I get the correct row put everything concatenated. If instead I put in a space in the " ".join.row I get the entire row separated with empty spaces - what I would like to do is access this row with

transaction_id = data[0]
                product = data[1]
                quantity = int(data[2])
                customer = data[3]
                date = parse_date(data[4])

but I always get an

IndexError: list index out of range

I also tried with data.replace(" ",";") but this gives me another error and the data type becomes a string instead of a list:

ValueError: invalid literal for int() with base 10: 'E'

Can someone please show me what I'm missing here?

python
2 Answers

I'm not sure why you are joining/splitting the row up. And you realize your split is using a semicolon?

I would expect something like this:

result = []
with open(f_name, 'r') as src:
    src.readline()  # burn the header row
    reader = csv.reader(src)   # if you want to use csv reader
    for line in reader:
        data = line.strip().split(',')   # strip any trailing whitespace and split it into elements by comma
        ...   either put it into result for list-of-lists or parse it out..

As far as your question goes... You mention extracting a "certain row" but you gave no indication how you would find such row. If you know the row index/number, you could burn lines with readline or such, or just keep a counter while you read. If you are looking for keyword in the data, just pop a conditional statement in either before or after splitting up the line.

AirSquid0

This way you can split the rows (and find which row you want based on some provided value)

with open('data.csv') as csv_file:
    csv_reader = csv.reader(csv_file, delimiter = ',')

    line_count = 0

    for row in csv_reader:
        # Line 0 is the header

        if line_count == 0:
            print(f'Column names are {", ".join(row)}')
            line_count += 1
        
        else:
            line_count += 1
            # Here you can check if the row value is equal what you're finding
            # row[0] = POS
            # row[1] = Transaction id
            # row[2] = Product
            # row[3] = Quantity
            # row[4] = Customer
            # row[5] = Date

            if row[2] = "TV":
                #If you want to add all variables into a single string:
                data = ",".join(row) 

                # Make each row into a single variable:
                transaction_id = row[0]
                product = row[1]
                quantity = row[2]
                customer = row[3]
                date = row[4]
Raphael Frei0
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