df <- tidyr::pivot_wider(df, id_cols = x, names_from = g, values_from = y)
matplot(df$x, y = df[, 2:ncol(df)], type = "l", col = "black", lty = "solid")
df <- tidyr::pivot_wider(df, id_cols = x, names_from = g, values_from = y)
matplot(df$x, y = df[, 2:ncol(df)], type = "l", col = "black", lty = "solid")