I need to rewrite a csv to a new file. In the new file the delta will be calculated and put into a column as well as the direction the delta moves

I’m trying to modify a csv but keep getting the error:

 modifiedFile.write(new)
ValueError: I/O operation on closed file.

The code I did is:

originalFileName = 'C:/Users/Janedoe/Desktop/My Projects/tickerinfo.csv'
modifiedFileName = 'C:/Users/Janedoe/Desktop/My Projects/tickerInfoWithDelta.csv'

def calculateDelta(o, c):
    oInt = float(closingPrice)
    cInt = float(openingPrice)
    calculatedDelta = (oInt-cInt)
    return calculatedDelta

def direction():
    if calculatedDelta > 0 :
        direction = 1
    else:
        direction = 0
    return direction

with open(originalFileName, 'r', encoding = 'utf8') as originalFile, open(modifiedFileName, 'w', encoding = 'utf8') as modifiedFile:
    header = 'Date,Close,Open,Delta,Direction'
    line = originalFile.readline()
    line = originalFile.readline()
while line != '':
    lineList = line.split(',')
    date = lineList[1]
    closingPrice = lineList[2]
    openingPrice = lineList[5]
    delta = calculateDelta(openingPrice, closingPrice)
    new = str(date) + ',' + str(closingPrice) + ',' + str(openingPrice) + ',' + str(delta) + ',' + str(direction) + '\n'
    modifiedFile.write(new)

When I open the modified file, it is blank. It’s for a beginner’s python course, so that being said my knowledge is limited and anything helps!

>Solution :

modifiedFile is "opened" on the with open line. After that indentation context ends, the file is closed.

You can’t write to a closed file.

One thing you can do is move the writes under that with open context (indentation).