Read specific columns with pandas or other python module

Question

I have a csv file from this webpage  I want to read some of the columns in the downloaded file  the csv version can be downloaded in the upper right corner    Let s say I want 2 columns    59 which in the header is star name 60 which in the header is ra    However  for some reason the authors of the webpage sometimes decide to move the columns around   In the end I want something like this  keeping in mind that values can be missing   data    read data in a clever way names   data  star name   ras   data  ra     This will prevent my program to malfunction when the columns are changed again in the future  if they keep the name correct   Until now I have tried various ways using the csv module and resently the pandas module  Both without any luck   EDIT  added two lines   the header of my datafile  Sorry  but it s extremely long      name  mass  mass error min  mass error max  radius  radius error min  radius error max  orbital period  orbital period err min  orbital period err max  semi major axis  semi major axis error min  semi major axis error max  eccentricity  eccentricity error min  eccentricity error max  angular distance  inclination  inclination error min  inclination error max  tzero tr  tzero tr error min  tzero tr error max  tzero tr sec  tzero tr sec error min  tzero tr sec error max  lambda angle  lambda angle error min  lambda angle error max  impact parameter  impact parameter error min  impact parameter error max  tzero vr  tzero vr error min  tzero vr error max  K  K error min  K error max  temp calculated  temp measured  hot point lon  albedo  albedo error min  albedo error max  log g  publication status  discovered  updated  omega  omega error min  omega error max  tperi  tperi error min  tperi error max  detection type  mass detection type  radius detection type  alternate names  molecules  star name  ra  dec  mag v  mag i  mag j  mag h  mag k  star distance  star metallicity  star mass  star radius  star sp type  star age  star teff  star detected disc  star magnetic field 11 Com b 19 4 1 5 1 5    326 03 0 32 0 32 1 29 0 05 0 05 0 231 0 005 0 005 0 011664                             1 2008 2011-12-23 94 8 1 5 1 5 2452899 6 1 6 1 6 Radial Velocity     11 Com 185 1791667 17 7927778 4 74     110 6 -0 35 2 7 19 0 G8 III  4742 0   11 UMi b 10 5 2 47 2 47    516 22 3 25 3 25 1 54 0 07 0 07 0 08 0 03 0 03 0 012887                             1 2009 2009-08-13 117 63 21 06 21 06 2452861 05 2 06 2 06 Radial Velocity     11 UMi 229 275 71 8238889 5 02     119 5 0 04 1 8 24 08 K4III 1 56 4340 0

User · Answer

According to the latest pandas documentation you can read a csv file selecting only the columns which you want to read.

import pandas as pd

df = pd.read_csv('some_data.csv', usecols = ['col1','col2'], low_memory = True)

Here we use usecols which reads only selected columns in a dataframe.

We are using low_memory so that we Internally process the file in chunks.

User · Answer

An easy way to do this is using the pandas library like this   import pandas as pd fields     star name    ra    df   pd read csv  data csv   skipinitialspace True  usecols fields    See the keys print df keys     See content in  star name  print df star name   The problem here was the skipinitialspace which remove the spaces in the header  So   star name  becomes  star name

User · Answer

Got a solution to above problem in a different way where in although i would read entire csv file  but would tweek the display part to show only the content which is desired   import pandas as pd  df   pd read csv  data csv   skipinitialspace True  print df   star name    ra      This one could help in some of the scenario s in learning basics and filtering data on the basis of columns in dataframe

User · Answer

Above answers are in python2  So for python 3 users I am giving this answer  You can use the bellow code  import pandas as pd fields     star name    ra    df   pd read csv  data csv   skipinitialspace True  usecols fields    See the keys print df keys      See content in  star name  print df star name

[python] Read specific columns with pandas or other python module

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