Python: Not able to read first row of csv file correctly using read_csv

Question

Trying to read the csv file through pandas, but it looks like it is not reading it correctly

Code:

pd.read_csv(data_file_path, sep=",", index_col=0, header=0, dtype = object)

For eg: My data is (in csv file):

12 1.43E+19 This is first line  101010  
23 1.43E+19 This is the second line 202020  
34 1.43E+19 This is the third line  303030

I am trying to read with first column as index.

Output:

     1.43E+19 This is first line    101010  
12  
23 1.43E+19 This is the second line 202020  
34 1.43E+19 This is the third line 303030

Output without making 1st column as index:

  12 1.43E+19 This is first line 101010  
0 23 1.43E+19 This is the second line 202020  
1 34 1.43E+19 This is the third line 303030

Because of this, any further processing on this data is ignoring the first row data.

DSM · Accepted Answer · 2014-12-23 01:51:59Z

1

I think you're confusing header=0, which means "use the 0-th row as the header", with header=None, which means "don't read a header from the file".

Compare:

>>> pd.read_csv("h.csv", header=0, index_col=0)
        1.43E+19       This is first line  101010  
12                                                 
23  1.430000e+19  This is the second line    202020
34  1.430000e+19   This is the third line    303030
>>> pd.read_csv("h.csv", header=None, index_col=0)
               1                        2       3
0                                                
12  1.430000e+19       This is first line  101010
23  1.430000e+19  This is the second line  202020
34  1.430000e+19   This is the third line  303030

You can also specify column names using names:

>>> pd.read_csv("h.csv", names=["Number", "Line", "Code"], index_col=0)
          Number                     Line    Code
12  1.430000e+19       This is first line  101010
23  1.430000e+19  This is the second line  202020
34  1.430000e+19   This is the third line  303030

PS: Since you're using sep="," but the file you showed doesn't have any commas, I'm assuming that you removed them for some reason when asking the question. If that's right, please don't: no one's afraid of commas, and it simply means that other people have to guess where to put them back in if they want to test your code.

answered Dec 23, 2014 at 1:51

DSM

355k67 gold badges606 silver badges504 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Himanshu Over a year ago

Aah.. I see. I thought header = 0 means "No header". My bad. Thanks for pointing it out. The code is working now. And I am reading data from csv file so copied the data directly from file to show here. Sorry for confusion.

Collectives™ on Stack Overflow

Python: Not able to read first row of csv file correctly using read_csv

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related