DataFrames

Introduction to Julia

James Fulton

Climate informatics researcher

Tabular data

	Day	Distance	Time	Raining
1	Wednesday	2000	14.99	true
2	Monday	5000	31.68	false
3	Thursday	3500	22.02	true
4	Tuesday	3000	17.25	true
5	Thursday	4500	25.47	false
6	Monday	5000	30.77	true

Tabular data

	Day	Distance	Time	Raining
1	Wednesday	2000	14.99	true
2	Monday	5000	31.68	false
3	Thursday	3500	22.02	true
4	Tuesday	3000	17.25	true
5	Thursday	4500	25.47	false
6	Monday	5000	30.77	true
	String	Int	Float	Bool

DataFrames

using DataFrames

# Create DataFrame
df = DataFrames.DataFrame(




)

DataFrames

using DataFrames

# Create DataFrame
df = DataFrame(

    day = ["Wednesday", "Monday", "Thursday", "Tuesday", "Thursday", "Monday"]

    distance = [2000, 5000, 3500, 3000, 4500, 5000]
    time = [14.99, 31.68, 22.02, 17.25, 25.47, 30.77]
    raining = [true, false, true, true, false, true]

)

DataFrames

using DataFrames

# Create DataFrame
df = DataFrame(

    day = ["Wednesday", "Monday", "Thursday", "Tuesday", "Thursday", "Monday"],
    distance = [2000, 5000, 3500, 3000, 4500, 5000],
    time = [14.99, 31.68, 22.02, 17.25, 25.47, 30.77],
    raining = [true, false, true, true, false, true],
)

DataFrames

println(df)

6×4 DataFrame   
 Row | day        distance  time     raining
     | String     Int64     Float64  Bool 
_____|______________________________________
   1 | Wednesday      2000    14.99     true
   2 | Monday         5000    31.68    false
   3 | Thursday       3500    22.02     true
   4 | Tuesday        3000    17.25     true
   5 | Thursday       4500    25.47    false
   6 | Monday         5000    30.77     true

CSV files

Comma separated variable
Common format for tabular data

Inside run.csv:

day,distance,time,raining
Wednesday,2000,14.99,true
Monday,5000,31.68,false
Thursday,3500,22.02,true
Tuesday,3000,17.25,true
Thursday,4500,25.47,false
Monday,5000,30.77,true

Loading CSV files

using CSV

# Load the run data
file = CSV.File("run.csv")


# Convert the CSV file into the DataFrame
df = DataFrame(file)

Cannot use File("run.csv") only CSV.File("run.csv")

Printing DataFrames

# Print the first 3 rows
println(first(df, 3))

3×4 DataFrame   
 Row | day        distance  time     raining
     | String     Int64     Float64  Bool 
_____|______________________________________
   1 | Wednesday      2000    14.99     true
   2 | Monday         5000    31.68    false
   3 | Thursday       3500    22.02     true

Basic properties of DataFrames

# Print column names
println(names(df))

["day", "distance", "time", "raining"]

# Print number of rows and columns
println(size(df))

(6, 4)

Let's practice!

Introduction to Julia