CODEWITHSUNDEEP
pythonpandasdata-science
Ola O
Ola O

Reputation: 25

How to Access Pandas dataframe columns when the number of columns are unknown before hand

I am new to python and data science altogether. I am writing a program to read and analyze a csv with pandas. The problem is that the csv will be supplied by the user and it can have variable number of columns depending on the user. I do not have a prior knowledge of the column names. I went about the problem by reading the csv using pandas and read the column names into a python list. However problem ensued when I attempted to access the dataframe column by supplying the indexed list as a column name. something like this:

#List of column names, coln
coln = df.columns
df.ix[:, df.coln[0]] # to access the first column of the dataframe.

But this did not work. Please help how do I do this? PLEASE HELP!

Upvotes: 1

Views: 3344

Answers (3)

A.Kot
A.Kot

Reputation: 7913

You should be using iloc and not the method I corrected below as the other answers show, but to fix your original error:

coln = df.columns
df.ix[:, coln[0]] # to access the first column of the dataframe.

You wrote df.coln[0] instead of coln[0]. coln is a list, there is no such thing as df.coln.

Upvotes: 0

jezrael
jezrael

Reputation: 863236

Better is use iloc:

df.iloc[:, 0]

output is same as:

coln = df.columns
print (df.ix[:, coln[0]])

Upvotes: 2

Alvaro Silvino
Alvaro Silvino

Reputation: 9753

You can use iloc

df.iloc[:,0]

Btw, df.coln does not exist you created coln as separate variable.

Upvotes: 0

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