Julia loop over dataframe columns

Question

I am trying to convert dataframe columns from string to int to boolean using a loop. I have confirmed that n does correctly catch the df column names but am unable to reference them in the convert statement.

for n in (names(df))
    df[!,:n] = convert.(Bool, (parse.(Int,df[!,:n])))
end

The error I get is:

ERROR: LoadError: ArgumentError: column name :n not found in the data frame

The problem is :n is a symbol and is not referring to n in your loop for n in ..., to refer to n use n not :n, i.e. the second line should be df[!,n] = convert.(Bool, (parse.(Int,df[!,n]))). — هنروقتان
– هنروقتان, Commented Feb 23, 2022 at 10:25

barpapapa · Accepted Answer · 2022-02-23 01:10:06Z

2

You shouldn't use : before the column names, and parse can parse a string as a Bool too.

transform!(df, names(df) .=> ByRow(x->parse(Bool, x)), renamecols = false)

answered Feb 23, 2022 at 1:10

barpapapa

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1 Comment

Bogumił Kamiński Over a year ago

or mapcols(x -> parse.(Bool, x), df),

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