Add New Column to Data Frame in for-Loop in R (Example Code)

This article illustrates how to append a new variable or row to a data frame in R using a for-loop.

Introduction of Example Data

data(iris)                                                 # Loading iris data set
head(iris)
#   Sepal.Length Sepal.Width Petal.Length Petal.Width Species
# 1          5.1         3.5          1.4         0.2  setosa
# 2          4.9         3.0          1.4         0.2  setosa
# 3          4.7         3.2          1.3         0.2  setosa
# 4          4.6         3.1          1.5         0.2  setosa
# 5          5.0         3.6          1.4         0.2  setosa
# 6          5.4         3.9          1.7         0.4  setosa

Example: Append New Column to Data Frame Using for-Loop in R

for(index in 1:3) {                                        # Running for-loop
  add_col <- paste0("index", index, "_row", 1:nrow(iris))  # Creating new variable
  iris[ , ncol(iris) + 1] <- add_col                       # Appending new variable to data
}
head(iris)                                                 # Showing new data
#   Sepal.Length Sepal.Width Petal.Length Petal.Width Species          V6          V7          V8
# 1          5.1         3.5          1.4         0.2  setosa index1_row1 index2_row1 index3_row1
# 2          4.9         3.0          1.4         0.2  setosa index1_row2 index2_row2 index3_row2
# 3          4.7         3.2          1.3         0.2  setosa index1_row3 index2_row3 index3_row3
# 4          4.6         3.1          1.5         0.2  setosa index1_row4 index2_row4 index3_row4
# 5          5.0         3.6          1.4         0.2  setosa index1_row5 index2_row5 index3_row5
# 6          5.4         3.9          1.7         0.4  setosa index1_row6 index2_row6 index3_row6

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