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如何将标题行添加到Pandas DataFrame

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问题：如何将标题行添加到Pandas DataFrame
回答 0
回答 1
回答 2
回答 3

问题：如何将标题行添加到Pandas DataFrame

我正在将csv文件读入pandas。此csv文件由四列和一些行组成，但没有要添加的标题行。我一直在尝试以下方法：

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')

但是，当我应用代码时，出现以下错误：

ValueError: Shape of passed values is (1, 1), indices imply (4, 1)

错误的确切含义是什么？在python中将标题行添加到csv文件/ pandas df的一种干净方法是什么？

点击查看英文原文

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?

回答 0

您可以names直接在read_csv

names：类似数组，默认为None要使用的列名列表。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"])
点击查看英文原文

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"])

回答 1

另外，您可以阅读csv，header=None然后添加df.columns：

Cov = pd.read_csv("path/to/file.txt", sep='\t', header=None)
Cov.columns = ["Sequence", "Start", "End", "Coverage"]
点击查看英文原文

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"]

回答 2

col_Names=["Sequence", "Start", "End", "Coverage"]
my_CSV_File= pd.read_csv("yourCSVFile.csv",names=col_Names)

完成此操作后，只需进行检查[显然，我知道，你知道。但是…

my_CSV_File.head()

希望对您有帮助…干杯

点击查看英文原文 
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

回答 3

要修复代码，您只需将更[Cov]改为Cov.values，第一个参数pd.DataFrame将变为多维numpy数组：

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')

但最聪明的解决方案仍然是pd.read_excel与header=None和一起使用names=columns_list。

点击查看英文原文

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.