Reading data from a CSV file in Python

Question

I am reading data from a CSV file (xyz.CSV) which contains below data:

col1,col2,col3,col4
name1,empId1,241682-27638-USD-CIGGNT ,1
name2,empId2,241682-27638-USD-OCGGINT ,1
name3,empId3,241942-37190-USD-GGDIV ,2
name4,empId4,241942-37190-USD-CHYOF ,1
name5,empId5,241942-37190-USD-EQPL ,1
name6,empId6,241942-37190-USD-INT ,1
name7,empId7,242066-15343-USD-CYJOF ,3
name8,empId8,242066-15343-USD-CYJOF ,3
name9,empId9,242066-15343-USD-CYJOF ,3
name10,empId10,241942-37190-USD-GGDIV ,2

When I am iterating it with a loop I am able to print the data row wise and and only column1 data by the below code.

file=open( path +"xyz.CSV", "r")
reader = csv.reader(file)
for line in reader:
    t=line[0]
    print t

By the above code I can only get the first column.

If I try to print line[1] or line[2] it gives me the below error.

    file=open( path +"xyz.CSV", "r")
    reader = csv.reader(file)
    for line in reader:
        t=line[1],[2]
        print t

t=line[1],line[2]
IndexError: list index out of range

Please suggest for printing the data of column2 or column3.

Does the csv file also contains xyz.CSV col1,col2,col3,col4. If that is the case then first line contains only one element i.e. ['xyz.CSV'] and then when you try to access [1] onwards it fails. — sk11
– sk11, Commented Nov 13, 2014 at 7:23
Possible duplicate of How do I read and write CSV files with Python? — Martin Thoma
– Martin Thoma, Commented Jan 11, 2017 at 7:45

Alderven · Accepted Answer · 2019-04-19 09:36:27Z

33

Here is how I've got 2nd and 3rd columns:

import csv

path = 'c:\\temp\\'

file=open( path +"xyz.CSV", "r")
reader = csv.reader(file)
for line in reader:
    t=line[1],line[2]
    print(t)

Here is the results:

('col2', 'col3')
('empId1', '241682-27638-USD-CIGGNT ')
('empId2', '241682-27638-USD-OCGGINT ')
('empId3', '241942-37190-USD-GGDIV ')
('empId4', '241942-37190-USD-CHYOF ')
('empId5', '241942-37190-USD-EQPL ')
('empId6', '241942-37190-USD-INT ')
('empId7', '242066-15343-USD-CYJOF ')
('empId8', '242066-15343-USD-CYJOF ')
('empId9', '242066-15343-USD-CYJOF ')
('empId10', '241942-37190-USD-GGDIV ')

edited Apr 19, 2019 at 9:36

answered Nov 13, 2014 at 7:28

Alderven

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Comments

Junaid · Accepted Answer · 2020-02-16 14:35:42Z

7

Although it's a pretty old question, just want to share my suggestion. Found it easier to read csv using pandas in a dataframe and access the data.

import pandas

df = pandas.read_csv('<path/to/your/csv/file>')

print(df)
#OUTPUT
#     col1     col2                       col3  col4
#0   name1   empId1   241682-27638-USD-CIGGNT      1
#1   name2   empId2  241682-27638-USD-OCGGINT      1
#2   name3   empId3    241942-37190-USD-GGDIV      2
#3   name4   empId4    241942-37190-USD-CHYOF      1
#4   name5   empId5     241942-37190-USD-EQPL      1
#5   name6   empId6      241942-37190-USD-INT      1
#6   name7   empId7    242066-15343-USD-CYJOF      3
#7   name8   empId8    242066-15343-USD-CYJOF      3
#8   name9   empId9    242066-15343-USD-CYJOF      3
#9  name10  empId10    241942-37190-USD-GGDIV      2

#you can access any column using

df['col2']
#OUTPUT
#0     empId1
#1     empId2
#2     empId3
#3     empId4
#4     empId5
#5     empId6
#6     empId7
#7     empId8
#8     empId9
#9    empId10
#Name: col2, dtype: object


#Or print a specific value using
df['col2'][0]

Update: I was mainly using Pandas in my project so found it easier to just use it to read the csv as well. There are other dedicated libraries available to read CSV (creating your own CSV reader should also be few lines of code).

edited Feb 16, 2020 at 14:35

answered Dec 5, 2019 at 14:26

Junaid

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2 Comments

4lberto Over a year ago

There is a standard library (csv) for this kind of tasks. Pandas is a dependency of 46MB with native libraries. If you use it in other parts of the project, ok, but just for this tasks of reading a CSV is a very bad practice

Junaid Over a year ago

@4lberto I was using using pandas in the project so didn't really explored other dedicated libraries. Answer updated as per your suggestion.

xecgr · Accepted Answer · 2014-11-13 07:27:02Z

4

Your first line only has one column, so the process fails and doesn't continue. To solve, just skip first row

>>> with open( path, "r") as file:
...     reader = csv.reader(file)
...     for idx,line in enumerate(reader):
...         if idx>0:
...             t=line[1],line[2]
...             print t
... 
('empId1', '241682-27638-USD-CIGGNT ')
('empId2', '241682-27638-USD-OCGGINT ')
('empId3', '241942-37190-USD-GGDIV ')
('empId4', '241942-37190-USD-CHYOF ')
('empId5', '241942-37190-USD-EQPL ')
('empId6', '241942-37190-USD-INT ')
('empId7', '242066-15343-USD-CYJOF ')
('empId8', '242066-15343-USD-CYJOF ')
('empId9', '242066-15343-USD-CYJOF ')
('empId10', '241942-37190-USD-GGDIV ')

answered Nov 13, 2014 at 7:27

xecgr

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Comments

Aakash Jain · Accepted Answer · 2014-11-13 07:22:07Z

1

Hope it clears the issue

import csv
file=open( "xyz.CSV", "r")
reader = csv.reader(file)
for line in reader:
    t=line[0]+","+line[1]
    print (t)

answered Nov 13, 2014 at 7:22

Aakash Jain

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2 Comments

Rohit Over a year ago

No it give the same Error as IndexError: list index out of range.

Aakash Jain Over a year ago

Strange!Its working fine on my machine. What are you assigning to t exactly?

Mayur Satav · Accepted Answer · 2020-06-21 13:23:38Z

1

you can also read csv data without importing pandas and csv

with open('testdata.csv', 'r') as f:
    results = []
    for line in f:
            words = line.split(',')
            results.append((words[0], words[1:]))
    print (results)

answered Jun 21, 2020 at 13:23

Mayur Satav

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Comments

Rabinzel · Accepted Answer · 2022-07-19 03:25:17Z

1

To read and write in a text file in Python, you can use the below syntax:

f = open('helloworld.txt', 'r')
message = f.read()
print(message)
f.close()


f = open('helloworld.txt', 'w')
f.write('hello world')
f.close()

To read the CSV file, follow the below code:

results = []
with open("C:/Users/Prateek/Desktop/TA Project/data1.csv") as inputfile:
    for line in inputfile:
    results.append(line.strip().split(','))

edited Jul 19, 2022 at 3:25

Rabinzel

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answered Feb 18, 2018 at 19:29

mickey

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Comments

Tanveer Alam · Accepted Answer · 2014-11-13 07:33:10Z

import csv
csv_file=open("xyz.csv", "r")
reader = csv.reader(csv_file)

for row in reader:
    print(" ".join(row[:2]))

Output :- 
col1 col2
name1 empId1
name2 empId2
name3 empId3
name4 empId4
name5 empId5
name6 empId6
name7 empId7
name8 empId8
name9 empId9
name10 empId10

Just put value in row as slice. Below is code for printing 2nd and 3rd coloumn.

import csv
csv_file=open("xyz.csv", "r")
reader = csv.reader(csv_file)

for row in reader:
    print(" ".join(row[1:3]))

output:
col2 col3
empId1 241682-27638-USD-CIGGNT 
empId2 241682-27638-USD-OCGGINT 
empId3 241942-37190-USD-GGDIV 
empId4 241942-37190-USD-CHYOF 
empId5 241942-37190-USD-EQPL 
empId6 241942-37190-USD-INT 
empId7 242066-15343-USD-CYJOF 
empId8 242066-15343-USD-CYJOF 
empId9 242066-15343-USD-CYJOF 
empId10 241942-37190-USD-GGDIV

ABHISHEK SRIVASTAVA · Accepted Answer · 2019-01-27 11:55:01Z

0

There is a simple method you can check out more at: Python CSV Docs

with open(filename, 'r') as csvfile:
        spamreader = csv.reader(csvfile, delimiter=' ', quotechar='|')
        for row in spamreader:
            data.append(row)

answered Jan 27, 2019 at 11:55

ABHISHEK SRIVASTAVA

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Comments

Max Lange · Accepted Answer · 2022-07-18 22:53:38Z

0

You can use tablebase.

Step 1: Open and store your CSV file.

import tablebase
MyTable = tablebase.CsvTable("<path/to/your/csv/file>")

Step 2: Get your column.

print(MyTable.get_col("ColumnName"))

This will return a list of your column content.

answered Jul 18, 2022 at 22:53

Max Lange

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Comments

Jacklin Salama · Accepted Answer · 2021-10-31 09:08:54Z

-2

load the preprocessed CSV data

data_preprocessed = pd.read_csv('file_name.csv')

answered Oct 31, 2021 at 9:08

Jacklin Salama

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1 Comment

Community Over a year ago

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