How to find maximum string length by column in data frame

Question

My question is similar to this. But for strings.

So I have a dataframe, each column contains strings of different length. So, how I can find the maximum string length per column?

Then, how to select the columns, where length is > 1, by sapply or similar.

A typical column of the dataframe looks like this:

clmn=c("XDX", "GUV", "FQ", "ACUE", "HIT", "AYX", "NFD", "AHBW", "GKQ", "PYF")

Thanks

Solution

We can use nchar

max(nchar(clmn))

For finding the maximum character length for each column

lapply(df1, function(x) max(nchar(x)))

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If we need to filter the columns that have maximum string length greater than 1

df1[sapply(df1, function(x) max(nchar(x)))>1]

Or

Filter(function(x) max(nchar(x)) >1, df1)