如何添加标题行到pandas DataFrame [英] How to add header row to a pandas DataFrame

问题描述

我正在读一个csv文件到 pandas 。这个csv文件包含四列和一些行，但没有标题行，我想添加。我一直在尝试以下：

  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'）
  

，我得到以下错误：

  ValueError：传递值的形状是（1,1），索引隐含）
  

错误是什么意思？在python中添加标题行到csv文件/ pandas df？

解决方案

names 直接在 read_csv

names：array-like，使用。如果文件
不包含标题行，则应显式传递header = None

  Cov = pd.read_csv（path / to / file.txt，sep ='\t'，
 names = [Sequence，Start，End，Coverage]）
  

下面的行不能正常工作。 Cov 已经是一个数据框架，假设它从文件中读取时确实有4列。

  Frame = pd.DataFrame（[Cov]，columns = [Sequence，Start，End，Coverage]）
  pre> 
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?
解决方案
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"])
The line below will not work as you expect. Cov is already a dataframe, assuming it really has 4 columns when it's being read from the file.
Frame=pd.DataFrame([Cov], columns = ["Sequence", "Start", "End", "Coverage"])


                        
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