Nsryjdtyk

I'm supposed to write a function that does this specifically.

def get_customer_record(file_handle, n):

    """

    -------------------------------------------------------

    Find the n-th record in a comma-delimited sequential file.

    Records are numbered starting with 0.

    Use: result = get_customer_record(file_handle, n)

    -------------------------------------------------------

    Parameters:

        file_handle - file to search (file - open for reading)

        n - the number of the record to return (int > 0)

    Returns:

        result - a list of the fields of the n-th record if it exists,

            an empty list otherwise (list)

    -------------------------------------------------------

    """

And here is the file.

customers.txt

12345,Tom,Black,300.00,1998-01-30

23456,Alice,Smith,1200.50,1998-02-20

14567,Jane,White,900.00,1998-07-01

43564,Weilin,Zhao,450.25,1998-01-03

45432,Bina,Mehta,278.95,1998-03-21

The Code

list =  

file_handle = open('customers.txt', 'r+', encoding="utf-8") 

line = file_handle.readline(n) 

list.append(line.strip(',')) 

file_handle.close() 

return list

A simple solution would be iterate through the file using next():

from csv import reader



def get_customer_record(file_handle, n):

    with open(file=file_handle) as csvfile:

        csv_reader = reader(csvfile)

        return next((line for row, line in enumerate(csv_reader) if row == n), )



print(get_customer_record(file_handle='customer.csv', n=3))

# ['43564', 'Weilin', 'Zhao', '450.25', '1998-01-03']



print(get_customer_record(file_handle='customer.csv', n=5))

# 

It's not clear from your syntax whether to return just the row as a string, or the fields split around the ,. I have assumed the single-line.

The python readline() function does not take an index, it just reads the next line from the file. Below I used readlines() (note the s) which reads all lines from the file. If your file was huge, this would not be so efficient.

Also a bit of error-handling for out-of-bounds n helps:

def get_customer_record(file_handle, n):

    lines = file_handle.readlines()

    if (n >= 0 and n < len(lines)):

        return lines[n] # or n-1?

    else:

        return None



file_handle = open( 'customers.txt', 'r+', encoding="utf-8" )

fields = get_customer_record( file_handle, 3 )

print( str( fields )  )

Of course you may not want to read the whole file, just the next Nth record

def get_customer_record(file_handle, n):

    if (n >= 0):

        line = file_handle.readline()

        while (n > 0):

            line = file_handle.readline()

            if (line == ''):

                line = None

                break  # end of file

            n -= 1

        return line

    else:

        return None

Obviously this code assumes that n is indexed 0 -> (N-1).