CSV File and TypeError: a bytes-like object

Question

I have a problem regarding to writing CSV file. Everytime I write my CSV file using python suddenly there is a blank space in every rows Here is the CSV file with blank space. So I search for the solution in the internet. Then some website says that I just need to change "w" to "wb" but after I try to run the program an error occur.

Error : TypeError: a bytes-like object is required, not 'str'

My Code :

seat =[]
csvfile = open('coba.csv') 
seating = csv.reader(csvfile)
for line in seating:
    seat.append(line)

print("Buy seat ?")
answer_1 = input("Answer : ")
if (answer_1 == "yes"):
    answer_2 = input("Enter preferred seat: ")
    if (answer_2 == "A1"):
        row = 1
        column = 0
        seat[row][column] = "X"
        writer = csv.writer(open('coba.csv', 'wb'))
        writer.writerows(seat)
        for line in seat:
            print(' | '.join(line))

CSV File :

[Business]
A1,A2,A3,A4,A5
B1,B2,B3,B4,B5
[Economy]
C1,C2,C3,C4,C5
D1,D2,D3,D4,D5

You get the error, because 'wb' expects binary data to be written, but the csv module attempts to write string. — Geshode, Dec 03 '18 at 01:56
The proper way to open a csv file in Python 3 is via `open(filenname, mode='r', newline='')` for reading and with `mode='w'` for writing (as shown in the examples in the [documentation](https://docs.python.org/3/library/csv.html#module-csv)). — martineau, Dec 03 '18 at 01:58
@AvivShai File "coba.py", line 163, in writer.writerows(seat) TypeError: a bytes-like object is required, not 'str' — DeltaTroz, Dec 03 '18 at 02:03
if i use notepad there is no blank space in everyrow, but if I use excel there is — DeltaTroz, Dec 03 '18 at 02:09

Krishna · Answer 1 · 2018-12-03T02:22:54.543

0

You are reading in 'r' and writing in 'wb'

You either have to change the data type of each element or simply

Change wb to w and it works

Full code

import csv

seat =[]
csvfile = open('coba.csv')
seating = csv.reader(csvfile)
for line in seating:
    seat.append(line)

print("Buy seat ?")
answer_1 = input("Answer : ")
if (answer_1 == "yes"):
    answer_2 = input("Enter preferred seat: ")
    if (answer_2 == "A1"):
        row = 1
        column = 0
        seat[row][column] = "X"
        writer = csv.writer(open('coba.csv', 'w'))
        writer.writerows(seat)
        for line in seat:
            print(' | '.join(line))

Output

Buy seat ?
Answer : yes
Enter preferred seat: A1
[Business]
X | A2 | A3 | A4 | A5
B1 | B2 | B3 | B4 | B5
[Economy]
C1 | C2 | C3 | C4 | C5
D1 | D2 | D3 | D4 | D5

Opening the generated file in excel

edited Dec 03 '18 at 02:22

answered Dec 03 '18 at 01:53

Krishna

924
1
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yeah i know it works if i use "w", but the problem is when i use "w" there is suddenly blank space every row – DeltaTroz Dec 03 '18 at 02:01
1

Are you on windows? If so try using `newline=''`. in line `csv.writer(open('coba.csv', 'w', newline=''))` – Krishna Dec 03 '18 at 02:02
tried already, only in excel random blank appear – DeltaTroz Dec 03 '18 at 02:18
You mean when opening the generated file in excel? – Krishna Dec 03 '18 at 02:19
yeah, so if I run the program for the second time all the position of my seat is messed up because of the blankspace in excel – DeltaTroz Dec 03 '18 at 02:20
I added the image of excel. I do not see any additional blank lines with `newline=''`. am I missing something? – Krishna Dec 03 '18 at 02:23
hmmm so it is my excel problem? – DeltaTroz Dec 03 '18 at 02:24
Not sure. What do you see in raw csv. Any additional new lines? – Krishna Dec 03 '18 at 02:27
no any blank line between any rows, the blank line appear after file is generated – DeltaTroz Dec 03 '18 at 02:28
this is frustating : – DeltaTroz Dec 03 '18 at 02:30
Try some alternatives for excel. Python also has library to write excel directly. try that. – Krishna Dec 03 '18 at 02:31
is it possible if I use txt file instead of csvfile for my program? – DeltaTroz Dec 03 '18 at 02:37
CSV is same as TXT file. There is no difference except the rules of CSV and extension. – Krishna Dec 03 '18 at 02:40
it is very confusing if I open the generated file using excel there is blankspace, but if open the excel file using notepad the all the blank lien appear in excel is missing.. – DeltaTroz Dec 03 '18 at 02:49
Can you try replacing X5 instead of X1. May be there is problem in input file itself. Wild guess I might be wrong – Krishna Dec 03 '18 at 02:54
what happen if I uninstall excel then operate the csv file using notepad? – DeltaTroz Dec 03 '18 at 03:10
That should be fine if that's acceptable for you – Krishna Dec 03 '18 at 03:32
i ahve unistall my excel, then the same problem appear again, everytime i read the file and put it in a list then print the list, there is a blank space in every rows.. This is frustasting – DeltaTroz Dec 04 '18 at 08:24

cssko · Answer 2 · 2018-12-03T02:02:38.293

Use the newline keyword argument in your open() calls,

seat = []
with open('coba.csv', 'r', newline='') as csvfile:
    seating = csv.reader(csvfile)
    for line in seating:
        seat.append(line)

print("Buy seat ?")
answer_1 = input("Answer : ")
if answer_1 == "yes":
    answer_2 = input("Enter preferred seat: ")
    if answer_2 == "A1":
        row = 1
        column = 0
        seat[row][column] = "X"
        with open('coba.csv', 'w', newline='') as csvfile:
            writer = csv.writer(csvfile)
            writer.writerows(seat)
            for line in seat:
                print(' | '.join(line))

try already using newline='' , there is still a blankspace every rows — DeltaTroz, Dec 03 '18 at 02:02

CSV File and TypeError: a bytes-like object

2 Answers2