CODEWITHSUNDEEP
pythoncsv
Binyamin Even
Binyamin Even

Reputation: 3382

Python grab a whole column from CSV file ignoring comma with double quotes

I am new to python. I want to grab a whole column from a *.csv file. in order to do so, I saw that my best way is to convert my csv to 2-dim. array using:

   > import numpy as np
   > csv=np.genfromtxt(file_name.csv, delimeter=",")

and than for example if I want to grab the 8-th column just to write:

column8=csv[:,7]

my problem is that I have fields, in double quotes, with a comma in them, so I have a ValueError:

ValueError: Some errors were detected !

Line #6 (got 16 columns instead of 15)

Line #21 (got 16 columns instead of 15)

Line #45 (got 18 columns instead of 15)

etc.

so all I want is, if for example this is my csv:

a,b,c,d

f,g,h,"i,j"

k,l,m,"n,o,p"

so if for example I want to grab the 4-th column I want the answer to be:

d

i,j

n,o,p

any ideas anyone??

thank you!!!

Upvotes: 0

Views: 427

Answers (4)

Daniel Lee
Daniel Lee

Reputation: 8011

Similarly to taleinat's solution, but if you know the header_name and want to return a list.

import csv

with open(FILENAME, "rb") as MEDIA:
headers = []
columns = []
required_header = "name"
csv_file = csv.reader(MEDIA, quoting=csv.QUOTE_NONE, delimiter=DELIMITER)
for row in csv_file:
    headers = row[:]
    break
position = headers.index(required_header)
[columns.append(row[position]) for row in csv_file]
return columns

Upvotes: 0

alexey
alexey

Reputation: 706

pandas is very good for reading from csv files.

try to use:

df = pandas.read_csv("filename.csv", delimeter=",") # header=None)

after this, to access a column

df['colname'] # or df[col_ind] if you set header=None

Upvotes: 0

taleinat
taleinat

Reputation: 8701

Python's built-in csv module takes care of this nicely with the default settings. So this should just work:

import csv
with open("file_name.csv", "r", newline='') as f:
    reader = csv.reader(f)
    column8 = [row[7] for row in reader]

This is a slight variation on the first example in the module's documentation, which contains additional useful information.

Upvotes: 1

Rohan Amrute
Rohan Amrute

Reputation: 774

Using pandas package will solve your problem. As pandas has a wide variety of methods from which we can read different file formats.

    import pandas as pd
    df = pd.read_csv("filename.csv")
    print df[column4]

Upvotes: 0

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