How To Read Only Specific Columns in Pandas read CSV

John D K -

To read only specific columns from CSV file using Pandas read_csv method we need to use parameter usecols=fields

Steps to read specific columns from CSV file

  • Import pandas
  • Define columns to be read
  • usecols=fields - to list columns to be read
    • Subset of columns to select, denoted either by column labels or column indices.
  • low_memory = True - reading in chunks
    • Internally process the file in chunks, resulting in lower memory use while parsing, but possibly mixed type inference.
  • index_col - to identify column X as index
    • Column(s) to use as row label(s), denoted either by column labels or column indices.
  • names and header to override the column names.

More information can be found: DataFrame.plot - secondary_y

Data

Suppose we have the following CSV file which we like to read with Pandas. We want to read only single column from this CSV file into DataFrame:

,x,y,z
0,a,e,1
1,b,f,2
2,c,g,3
3,d,i,4
x y z
0 a e 1
1 b f 2
2 c g 3
3 d i 4

Example

import pandas as pd
cols = ['x', 'y']
df = pd.read_csv('data/data_0.csv', usecols = cols, low_memory = True)

Output

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