Monday Morning Exercises

These are exercises that we will do in the optional class on Monday morning for those who want more practice data manipulation with tidyverse. If you can do these coding challenges with little difficulty, there is no need to attend the Monday class. Note: We will work with two the iris and mtcars data sets - while these have nothing to do with RNA-Seq, the skills you develop will translate directly to count or expression data from RNA-Seq experiments.

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1. Warm up with the iris data frame.

  • Show the first 3 rows
  • Show the last 3 rows
  • Show 3 random rows without repetition
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2. Using the iris data set,

  • Find the mean value of all 4 measurements
  • Find the mean value of all 4 measurements for each Species
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3. Using the iris data set,

  • Sort the observations by Sepal.Width in decreasing order.
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4. Using the iris data`m set,

  • Count the number of flowers of each Species
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5. Using the iris data set,

  • Count the number of observations where Petal.Length is longer than Sepal.Width
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6. Using the iris data set,

  • Find the Species with the most number of observations where the Sepal.Length is less then the mean Sepal.Length of all observations
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7. Using the iris data set,

  • Convert the data frame from the current wide format to a tall format, with just 3 columns: Species, Measurement, Value.
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8. Using the mtcars data set,

  • Find the mean weight of all cars with mpg > 20 and cyl = 4.
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9. Using the mtcars data set,

  • Add a new column named bmi that is equal to (hp*mpg/wt)
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10. Using the mtcars data set

  • Find all rows whose car names have numbers in them.
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