@slice

Slicing rows is similar to filtering rows, except that slicing is performed based on row numbers rather tha filter criteria. In Tidier.jl, slicing works similarly to R's tidyverse in that both positive (which rows to keep) and negative (which rows to remove) slicing is supported. For @slice(), any valid UnitRange of integers is considered valid; this is not the case for @select() or across().

Remember: Just like every other Tidier.jl top-level macro, @slice() respects group. This means that in a grouped data frame, @slice(1:2) will select the first 2 rows from each group.

using Tidier
using RDatasets

movies = dataset("ggplot2", "movies");

Slicing using a range of numbers

This is an easy way of retrieving 5 consecutive rows.

@chain movies begin
    @slice(1:5)
    @select(1:5)
end

5×5 DataFrame

Row	Title	Year	Length	Budget	Rating
	String	Int32	Int32	Int32?	Float64
1	$	1971	121	missing	6.4
2	$1000 a Touchdown	1939	71	missing	6.0
3	$21 a Day Once a Month	1941	7	missing	8.2
4	$40,000	1996	70	missing	8.2
5	$50,000 Climax Show, The	1975	71	missing	3.4

Slicing using a more complex UnitRange of numbers

How would we obtain every other from 1 to 7 (counting up by 2)? Note that range() is similar to seq() in R.

@chain movies begin
  @slice(range(start = 1, step = 2, stop = 7))
  @select(1:5)
end

4×5 DataFrame

Row	Title	Year	Length	Budget	Rating
	String	Int32	Int32	Int32?	Float64
1	$	1971	121	missing	6.4
2	$21 a Day Once a Month	1941	7	missing	8.2
3	$50,000 Climax Show, The	1975	71	missing	3.4
4	$windle	2002	93	missing	5.3

This same code can also be written using Julia's shorthand syntax for unit ranges.

@chain movies begin
  @slice(1:2:7)
  @select(1:5)
end

4×5 DataFrame

Row	Title	Year	Length	Budget	Rating
	String	Int32	Int32	Int32?	Float64
1	$	1971	121	missing	6.4
2	$21 a Day Once a Month	1941	7	missing	8.2
3	$50,000 Climax Show, The	1975	71	missing	3.4
4	$windle	2002	93	missing	5.3

Separate multiple row selections with commas

If you have multiple different row selections, you can separate them with commas.

@chain movies begin
    @slice(1:5, 10)
    @select(1:5)
end

6×5 DataFrame

Row	Title	Year	Length	Budget	Rating
	String	Int32	Int32	Int32?	Float64
1	$	1971	121	missing	6.4
2	$1000 a Touchdown	1939	71	missing	6.0
3	$21 a Day Once a Month	1941	7	missing	8.2
4	$40,000	1996	70	missing	8.2
5	$50,000 Climax Show, The	1975	71	missing	3.4
6	'49-'17	1917	61	missing	6.0

Inverted selection using negative numbers

This line selects all rows except the first 5 rows. For the sake of brevity, we are only showing the first 5 of the remaining results.

@chain movies begin
    @slice(-(1:5))
    @select(1:5)
    @slice(1:5)
end

5×5 DataFrame

Row	Title	Year	Length	Budget	Rating
	String	Int32	Int32	Int32?	Float64
1	$pent	2000	91	missing	4.3
2	$windle	2002	93	missing	5.3
3	'15'	2002	25	missing	6.7
4	'38	1987	97	missing	6.6
5	'49-'17	1917	61	missing	6.0

---

This page was generated using Literate.jl.