Write CSV Python

Question

I want write csv (outfile) file from another csv file (infile). In infile csv data write like this OF0A0C,00,D0,0F11AFCB I want to write to outfile same asinfile but I get like this "\r \n 0,F,0,A,0,C,","0,0,","D,0,","0,F,1,1,A,F,C,B \r \n My code like this :

with open ("from_baryon.csv", "r") as inFile:
    with open (self.filename, "a") as outFile:
        for line in inFile:
            OutFile = csv.writer (outFile)
            OutFile.writerow (line)

After write I want to save every data in row to list like this Data = [[length_of_all_data],[length_data_row_1,datarow1],[length_data_row_2,datarow1datarow2],[length_data_row_3,datarow1datarow3]]

I confused to save the with list mode like that. Thankyou

Anand S Kumar · Accepted Answer · 2015-10-12 09:55:10Z

2

Few issues -

You should read the input csv file using csv module's csv.reader() , instead of iterating over its lines, since when you iterate over its lines, you get the line back as a string in the iteration - for line in inFile: , and then you are writing this line back using OutFile.writerow(line) , hence it writes each character into different columns.
You do not need to create separate OutFile = csv.writer (outFile) for every line.

Example code -

with open ("from_baryon.csv", "r") as inFile:
    with open (self.filename, "a") as outFile:
        out_file = csv.writer (outFile)
        in_reader = csv.reader(inFile)
        for row in in_reader:
            out_file.writerow(row)

EDIT: For the second issue that is updated, you can create a list and a counter to keep track of the complete length. Example -

with open ("from_baryon.csv", "r") as inFile:
    with open (self.filename, "a") as outFile:
        out_file = csv.writer (outFile)
        in_reader = csv.reader(inFile)
        data = []
        lencount = 0
        for row in in_reader:
            out_file.writerow(row)
            tlen = len(''.join(row))
            data.append([tlen] + row)
            lencount += tlen
        data.insert(0,[lencount])

edited Oct 12, 2015 at 9:55

answered Oct 12, 2015 at 9:24

Anand S Kumar

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7 Comments

Imam Abdul Mahmudi Over a year ago

Thank you, it solved my first problem. Do you have any idea for second problem?

Anand S Kumar Over a year ago

What is the second problem? I didn't clearly understand. Are you looking for OutFile.writerows(data) ?

Imam Abdul Mahmudi Over a year ago

No, I just edit my post. My second problem is save to list

Anand S Kumar Over a year ago

For second issue, you can explain with examples?

Imam Abdul Mahmudi Over a year ago

Example: In my outfile csv the data like this : "0F0A0C,00,0FF11C", "0F0A0C,00,0FF11D" I want save to list like this : [[32],[16,0F0A0C,00,0FF11C],[16,0F0A0C,00,0FF11C]] thank you.

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