shuffle()

shuffle()

The shuffle() function will mix up, or "shuffle", the values in a column into a randomized order. It is one possible method for simulating a random data generating process (DGP).

Example 1:

One way to see how the shuffle() function works is by comparing a column before and after shuffling the variable. 

# Shuffle the Tip values and save them as a new variable in the data frame
TipExperiment$Tip_shuffled <- shuffle(TipExperiment$Tip)
# Shuffle the Condition values and save them as a new variable in the data frame
TipExperiment$Condition_shuffled <- shuffle(TipExperiment$Condition)
# Print out a few rows to compare the original values to the shuffled values
head(select(TipExperiment, Tip, Tip_shuffled, Condition, Condition_shuffled), 10)

Example output from running the code above:
output showing ten rows of Tip, Condition, and shuffled Tip and shuffled Condition


Example 2:

The shuffle() function can also be useful for constructing sampling distributions of various statistics (e.g., b1, PRE, F).

# Generate 1000 b1 estimates from a random DGP, and save into a data frame
sampling_dist_of_random_b1s <- do(1000) * b1(shuffle(Tip) ~ Condition, data = TipExperiment)
# Take a look at some of the data frame
head(sampling_dist_of_random_b1s)
# Plot the distribution of those 1000 random b1 estimates
gf_histogram(~b1, data = sampling_dist_of_random_b1s)

Example output from running the code above:
R output showing the first 6 rows of sampling_dist_of_random_b1s
Histogram of all the b1 estimates in sampling_dist_of_random_b1s​

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