theDF <- data.frame(A=1:10, B=11:20, C=1:10, D=11:20)
colsToFront(theDF, c('B', 'C'))
colsToFront(theDF, c('C', 'B'))
colsToFront(theDF, c('C', 'C'))
colsToBack(theDF, c('C', 'C'))
colsToBack(theDF, c('C', 'B'))
colsToBack(theDF, c('C', 'C'))
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