How to add header row to a pandas DataFrame
PythonCsvPandasHeaderPython Problem Overview
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?
Python Solutions
Solution 1 - Python
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"])
Solution 2 - Python
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"]
Solution 3 - Python
col_Names=["Sequence", "Start", "End", "Coverage"]
my_CSV_File= pd.read_csv("yourCSVFile.csv",names=col_Names)
having done this, just check it with:
my_CSV_File.head()
Solution 4 - Python
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.
Solution 5 - Python
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.
Solution 6 - Python
Since this is mentioned that we are reading from a csv, so the delimiter should be ','[as default, not need to mention]' and the given file has no header so header=None`
Sample Code :
import pandas as pd
data = pd.read_csv('path/to/file.txt',header=None)
data.columns = ["Sequence", "Start", "End", "Coverage"]
print(data.head()) #Print the first rows