How to check if a column exists in Pandas

Question

Is there a way to check if a column exists in a Pandas DataFrame   Suppose that I have the following DataFrame    gt  gt  gt  import pandas as pd  gt  gt  gt  from random import randint  gt  gt  gt  df   pd DataFrame   A    randint 1  9  for x in xrange 10                            B    randint 1  9  10 for x in xrange 10                            C    randint 1  9  100 for x in xrange 10      gt  gt  gt  df    A   B    C 0  3  40  100 1  6  30  200 2  7  70  800 3  3  50  200 4  7  50  400 5  4  10  400 6  3  70  500 7  8  30  200 8  3  40  800 9  6  60  200   and I want to calculate df  sum     df  A     df  C    But first I want to check if df  A   exists  and if not  I want to calculate df  sum     df  B     df  C   instead

User · Accepted Answer

This will work   if  A  in df    But for clarity  I d probably write it as   if  A  in df columns

User · Answer

To check if one or more columns all exist  you can use set issubset  as in   if set   A   C    issubset df columns      df  sum     df  A     df  C                     As  brianpck points out in a comment  set     can alternatively be constructed with curly braces   if   A    C   issubset df columns     See this question for a discussion of the curly-braces syntax   Or  you can use a list comprehension  as in   if all  item in df columns for item in   A   C

User · Answer

Just to suggest another way without using if statements  you can use the get   method for DataFrames  For performing the sum based on the question   df  sum     df get  A   df  B      df  C     The DataFrame get method has similar behavior as python dictionaries

[python] How to check if a column exists in Pandas

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