How to add header row to a pandas DataFrame
I am reading a csv file into pandas
. This csv file constists of four columns and some rows, but does not have a header row, which I want to add. I have been trying the following:
Cov = pd.read_csv("path/to/file.txt", sep='\t')
Frame=pd.DataFrame([Cov], columns = ["Sequence", "Start", "End", "Coverage"])
Frame.to_csv("path/to/file.txt", sep='\t')
But when I apply the code, I get the following Error:
ValueError: Shape of passed values is (1, 1), indices imply (4, 1)
What exactly does the error mean? And what would be a clean way in python to add a header row to my csv file/pandas df?
You can use names
directly in the read_csv
names : array-like, default None List of column names to use. If file contains no header row, then you should explicitly pass header=None
Cov = pd.read_csv("path/to/file.txt",
sep='\t',
names=["Sequence", "Start", "End", "Coverage"])
Alternatively you could read you csv with header=None
and then add it with df.columns
:
Cov = pd.read_csv("path/to/file.txt", sep='\t', header=None)
Cov.columns = ["Sequence", "Start", "End", "Coverage"]
col_Names=["Sequence", "Start", "End", "Coverage"]
my_CSV_File= pd.read_csv("yourCSVFile.csv",names=col_Names)
having done this, just check it with[well obviously I know, u know that. But still...
my_CSV_File.head()
Hope it helps ... Cheers
To fix your code you can simply change [Cov]
to Cov.values
, the first parameter of pd.DataFrame
will become a multi-dimensional numpy
array:
Cov = pd.read_csv("path/to/file.txt", sep='\t')
Frame=pd.DataFrame(Cov.values, columns = ["Sequence", "Start", "End", "Coverage"])
Frame.to_csv("path/to/file.txt", sep='\t')
But the smartest solution still is use pd.read_excel
with header=None
and names=columns_list
.
Simple And Easy Solution:
import pandas as pd
df = pd.read_csv("path/to/file.txt", sep='\t')
headers = ["Sequence", "Start", "End", "Coverage"]
df.columns = headers
NOTE: Make sure your header length and CSV file header length should not mismatch.