# Getting started with the plyranges package
Author: Stuart Lee
Date: 2021-05-19

Stuart Lee

#### 2021-05-19

#### Package

plyranges 1.12.0

# 1 `Ranges` revisited

In Bioconductor there are two classes, `IRanges` and `GRanges`, that are standard data structures for representing genomics data. Throughout this document I refer to either of these classes as `Ranges` if an operation can be performed on either class, otherwise I explicitly mention if a function is appropriate for an `IRanges` or `GRanges`.

`Ranges` objects can either represent sets of integers as `IRanges` (which have start, end and width attributes) or represent genomic intervals (which have additional attributes, sequence name, and strand) as `GRanges`. In addition, both types of `Ranges` can store information about their intervals as metadata columns (for example GC content over a genomic interval).

`Ranges` objects follow the tidy data principle: each row of a `Ranges` object corresponds to an interval, while each column will represent a variable about that interval, and generally each object will represent a single unit of observation (like gene annotations).

Consequently, `Ranges` objects provide a powerful representation for reasoning about genomic data. In this vignette, you will learn more about `Ranges` objects and how via grouping, restriction and summarisation you can perform common data tasks.

# 2 Constructing `Ranges`

To construct an `IRanges` we require that there are at least two columns that represent at either a starting coordinate, finishing coordinate or the width of the interval.

    suppressPackageStartupMessages(library(plyranges))
    set.seed(100)
    df <- data.frame(start=c(2:-1, 13:15),
                     width=c(0:3, 2:0))

    # produces IRanges
    rng <- df %>% as_iranges()
    rng

    ## IRanges object with 7 ranges and 0 metadata columns:
    ##           start       end     width
    ##       <integer> <integer> <integer>
    ##   [1]         2         1         0
    ##   [2]         1         1         1
    ##   [3]         0         1         2
    ##   [4]        -1         1         3
    ##   [5]        13        14         2
    ##   [6]        14        14         1
    ##   [7]        15        14         0

To construct a `GRanges` we require a column that represents that sequence name ( contig or chromosome id), and an optional column to represent the strandedness of an interval.

    # seqname is required for GRanges, metadata is automatically kept
    grng <- df %>%
      transform(seqnames = sample(c("chr1", "chr2"), 7, replace = TRUE),
             strand = sample(c("+", "-"), 7, replace = TRUE),
             gc = runif(7)) %>%
      as_granges()

    grng

    ## GRanges object with 7 ranges and 1 metadata column:
    ##       seqnames    ranges strand |        gc
    ##          <Rle> <IRanges>  <Rle> | <numeric>
    ##   [1]     chr2       2-1      - |  0.762551
    ##   [2]     chr1         1      - |  0.669022
    ##   [3]     chr2       0-1      + |  0.204612
    ##   [4]     chr2      -1-1      - |  0.357525
    ##   [5]     chr1     13-14      - |  0.359475
    ##   [6]     chr1        14      - |  0.690291
    ##   [7]     chr2     15-14      - |  0.535811
    ##   -------
    ##   seqinfo: 2 sequences from an unspecified genome; no seqlengths

# 3 Arithmetic on Ranges

Sometimes you want to modify a genomic interval by altering the width of the interval while leaving the start, end or midpoint of the coordinates unaltered. This is achieved with the `mutate` verb along with `anchor_*` adverbs.

The act of anchoring fixes either the start, end, center coordinates of the `Range` object, as shown in the figure and code below and anchors are used in combination with either `mutate` or `stretch`.

    rng <- as_iranges(data.frame(start=c(1, 2, 3), end=c(5, 2, 8)))
    grng <- as_granges(data.frame(start=c(1, 2, 3), end=c(5, 2, 8),
                              seqnames = "seq1",
                              strand = c("+", "*", "-")))
    mutate(rng, width = 10)

    ## IRanges object with 3 ranges and 0 metadata columns:
    ##           start       end     width
    ##       <integer> <integer> <integer>
    ##   [1]         1        10        10
    ##   [2]         2        11        10
    ##   [3]         3        12        10

    mutate(anchor_start(rng), width = 10)

    ## IRanges object with 3 ranges and 0 metadata columns:
    ##           start       end     width
    ##       <integer> <integer> <integer>
    ##   [1]         1        10        10
    ##   [2]         2        11        10
    ##   [3]         3        12        10

    mutate(anchor_end(rng), width = 10)

    ## IRanges object with 3 ranges and 0 metadata columns:
    ##           start       end     width
    ##       <integer> <integer> <integer>
    ##   [1]        -4         5        10
    ##   [2]        -7         2        10
    ##   [3]        -1         8        10

    mutate(anchor_center(rng), width = 10)

    ## IRanges object with 3 ranges and 0 metadata columns:
    ##           start       end     width
    ##       <integer> <integer> <integer>
    ##   [1]        -2         7        10
    ##   [2]        -3         6        10
    ##   [3]         1        10        10

    mutate(anchor_3p(grng), width = 10) # leave negative strand fixed

    ## GRanges object with 3 ranges and 0 metadata columns:
    ##       seqnames    ranges strand
    ##          <Rle> <IRanges>  <Rle>
    ##   [1]     seq1      -4-5      +
    ##   [2]     seq1      -7-2      *
    ##   [3]     seq1      3-12      -
    ##   -------
    ##   seqinfo: 1 sequence from an unspecified genome; no seqlengths

    mutate(anchor_5p(grng), width = 10) # leave positive strand fixed

    ## GRanges object with 3 ranges and 0 metadata columns:
    ##       seqnames    ranges strand
    ##          <Rle> <IRanges>  <Rle>
    ##   [1]     seq1      1-10      +
    ##   [2]     seq1      2-11      *
    ##   [3]     seq1      -1-8      -
    ##   -------
    ##   seqinfo: 1 sequence from an unspecified genome; no seqlengths

Similarly, you can modify the width of an interval using the `stretch` verb. Without anchoring, this function will extend the interval in either direction by an integer amount. With anchoring, either the start, end or midpoint are preserved.

    rng2 <- stretch(anchor_center(rng), 10)
    rng2

    ## IRanges object with 3 ranges and 0 metadata columns:
    ##           start       end     width
    ##       <integer> <integer> <integer>
    ##   [1]        -4        10        15
    ##   [2]        -3         7        11
    ##   [3]        -2        13        16

    stretch(anchor_end(rng2), 10)

    ## IRanges object with 3 ranges and 0 metadata columns:
    ##           start       end     width
    ##       <integer> <integer> <integer>
    ##   [1]       -14        10        25
    ##   [2]       -13         7        21
    ##   [3]       -12        13        26

    stretch(anchor_start(rng2), 10)

    ## IRanges object with 3 ranges and 0 metadata columns:
    ##           start       end     width
    ##       <integer> <integer> <integer>
    ##   [1]        -4        20        25
    ##   [2]        -3        17        21
    ##   [3]        -2        23        26

    stretch(anchor_3p(grng), 10)

    ## GRanges object with 3 ranges and 0 metadata columns:
    ##       seqnames    ranges strand
    ##          <Rle> <IRanges>  <Rle>
    ##   [1]     seq1      -9-5      +
    ##   [2]     seq1      -8-2      *
    ##   [3]     seq1      3-18      -
    ##   -------
    ##   seqinfo: 1 sequence from an unspecified genome; no seqlengths

    stretch(anchor_5p(grng), 10)

    ## GRanges object with 3 ranges and 0 metadata columns:
    ##       seqnames    ranges strand
    ##          <Rle> <IRanges>  <Rle>
    ##   [1]     seq1      1-15      +
    ##   [2]     seq1      2-12      *
    ##   [3]     seq1      -7-8      -
    ##   -------
    ##   seqinfo: 1 sequence from an unspecified genome; no seqlengths

`Ranges` can be shifted left or right. If strand information is available we can also shift upstream or downstream.

    shift_left(rng, 10)

    ## IRanges object with 3 ranges and 0 metadata columns:
    ##           start       end     width
    ##       <integer> <integer> <integer>
    ##   [1]        -9        -5         5
    ##   [2]        -8        -8         1
    ##   [3]        -7        -2         6

    shift_right(rng, 10)

    ## IRanges object with 3 ranges and 0 metadata columns:
    ##           start       end     width
    ##       <integer> <integer> <integer>
    ##   [1]        11        15         5
    ##   [2]        12        12         1
    ##   [3]        13        18         6

    shift_upstream(grng, 10)

    ## GRanges object with 3 ranges and 0 metadata columns:
    ##       seqnames    ranges strand
    ##          <Rle> <IRanges>  <Rle>
    ##   [1]     seq1     -9--5      +
    ##   [2]     seq1        -8      *
    ##   [3]     seq1     13-18      -
    ##   -------
    ##   seqinfo: 1 sequence from an unspecified genome; no seqlengths

    shift_downstream(grng, 10)

    ## GRanges object with 3 ranges and 0 metadata columns:
    ##       seqnames    ranges strand
    ##          <Rle> <IRanges>  <Rle>
    ##   [1]     seq1     11-15      +
    ##   [2]     seq1        12      *
    ##   [3]     seq1     -7--2      -
    ##   -------
    ##   seqinfo: 1 sequence from an unspecified genome; no seqlengths

# 4 Grouping `Ranges`

`plyranges` introduces a new class of `Ranges` called `RangesGrouped`, this is a similar idea to the grouped `data.frame\tibble` in `dplyr`.

Grouping can act on either the core components or the metadata columns of a `Ranges` object.

It is most effective when combined with other verbs such as `mutate()`, `summarise()`, `filter()`, `reduce_ranges()` or `disjoin_ranges()`.

    grng <- data.frame(seqnames = sample(c("chr1", "chr2"), 7, replace = TRUE),
             strand = sample(c("+", "-"), 7, replace = TRUE),
             gc = runif(7),
             start = 1:7,
             width = 10) %>%
      as_granges()

    grng_by_strand <- grng %>%
      group_by(strand)

    grng_by_strand

    ## GRanges object with 7 ranges and 1 metadata column:
    ## Groups: strand [2]
    ##       seqnames    ranges strand |        gc
    ##          <Rle> <IRanges>  <Rle> | <numeric>
    ##   [1]     chr2      1-10      - |  0.889454
    ##   [2]     chr2      2-11      + |  0.180407
    ##   [3]     chr1      3-12      - |  0.629391
    ##   [4]     chr2      4-13      + |  0.989564
    ##   [5]     chr1      5-14      - |  0.130289
    ##   [6]     chr1      6-15      - |  0.330661
    ##   [7]     chr2      7-16      - |  0.865121
    ##   -------
    ##   seqinfo: 2 sequences from an unspecified genome; no seqlengths

# 5 Restricting `Ranges`

The verb `filter` can be used to restrict rows in the `Ranges`. Note that grouping will cause the `filter` to act within each group of the data.

    grng %>% filter(gc < 0.3)

    ## GRanges object with 2 ranges and 1 metadata column:
    ##       seqnames    ranges strand |        gc
    ##          <Rle> <IRanges>  <Rle> | <numeric>
    ##   [1]     chr2      2-11      + |  0.180407
    ##   [2]     chr1      5-14      - |  0.130289
    ##   -------
    ##   seqinfo: 2 sequences from an unspecified genome; no seqlengths

    # filtering by group
    grng_by_strand %>% filter(gc == max(gc))

    ## GRanges object with 2 ranges and 1 metadata column:
    ## Groups: strand [2]
    ##       seqnames    ranges strand |        gc
    ##          <Rle> <IRanges>  <Rle> | <numeric>
    ##   [1]     chr2      1-10      - |  0.889454
    ##   [2]     chr2      4-13      + |  0.989564
    ##   -------
    ##   seqinfo: 2 sequences from an unspecified genome; no seqlengths

We also provide the convenience methods `filter_by_overlaps` and `filter_by_non_overlaps` for restricting by any overlapping `Ranges`.

    ir0 <- data.frame(start = c(5,10, 15,20), width = 5) %>%
      as_iranges()
    ir1 <- data.frame(start = 2:6, width = 3:7) %>%
      as_iranges()
    ir0

    ## IRanges object with 4 ranges and 0 metadata columns:
    ##           start       end     width
    ##       <integer> <integer> <integer>
    ##   [1]         5         9         5
    ##   [2]        10        14         5
    ##   [3]        15        19         5
    ##   [4]        20        24         5

    ir1

    ## IRanges object with 5 ranges and 0 metadata columns:
    ##           start       end     width
    ##       <integer> <integer> <integer>
    ##   [1]         2         4         3
    ##   [2]         3         6         4
    ##   [3]         4         8         5
    ##   [4]         5        10         6
    ##   [5]         6        12         7

    ir0 %>% filter_by_overlaps(ir1)

    ## IRanges object with 2 ranges and 0 metadata columns:
    ##           start       end     width
    ##       <integer> <integer> <integer>
    ##   [1]         5         9         5
    ##   [2]        10        14         5

    ir0 %>% filter_by_non_overlaps(ir1)

    ## IRanges object with 2 ranges and 0 metadata columns:
    ##           start       end     width
    ##       <integer> <integer> <integer>
    ##   [1]        15        19         5
    ##   [2]        20        24         5

# 6 Summarising `Ranges`

The `summarise` function will return a `DataFrame` because the information required to return a `Ranges` object is lost. It is often most useful to use `summarise()` in combination with the `group_by()` family of functions.

    ir1 <- ir1 %>%
      mutate(gc = runif(length(.)))

    ir0 %>%
      group_by_overlaps(ir1) %>%
      summarise(gc = mean(gc))

    ## DataFrame with 2 rows and 2 columns
    ##       query        gc
    ##   <integer> <numeric>
    ## 1         1  0.675555
    ## 2         2  0.635795

# 7 Joins, or another way at looking at overlaps between `Ranges`

A join acts on two GRanges objects, a query and a subject.

    query <- data.frame(seqnames = "chr1",
                   strand = c("+", "-"),
                   start = c(1, 9),
                   end =  c(7, 10),
                   key.a = letters[1:2]) %>%
      as_granges()

    subject <- data.frame(seqnames = "chr1",
                   strand = c("-", "+"),
                   start = c(2, 6),
                   end = c(4, 8),
                   key.b = LETTERS[1:2]) %>%
      as_granges()

Figure 1: Query and Subject Ranges

The join operator is relational in the sense that metadata from the query and subject ranges is retained in the joined range. All join operators in the `plyranges` DSL generate a set of hits based on overlap or proximity of ranges and use those hits to merge the two datasets in different ways. There are four supported matching algorithms: overlap, nearest, precede, and follow. We can further restrict the matching by whether the query is completely within the subject, and adding the directed suffix ensures that matching ranges have the same direction (strand).

The first function, `join_overlap_intersect()` will return a `Ranges` object where the start, end, and width coordinates correspond to the amount of any overlap between the left and right input `Ranges`. It also returns any metadatain the subject range if the subject overlaps the query.

    intersect_rng <- join_overlap_intersect(query, subject)
    intersect_rng

    ## GRanges object with 2 ranges and 2 metadata columns:
    ##       seqnames    ranges strand |       key.a       key.b
    ##          <Rle> <IRanges>  <Rle> | <character> <character>
    ##   [1]     chr1       2-4      + |           a           A
    ##   [2]     chr1       6-7      + |           a           B
    ##   -------
    ##   seqinfo: 1 sequence from an unspecified genome; no seqlengths

Figure 2: Intersect Join

The `join_overlap_inner()` function will return the `Ranges` in the query that overlap any `Ranges` in the subject. Like the `join_overlap_intersect()` function metadata of the subject `Range` is returned if it overlaps the query.

    inner_rng <- join_overlap_inner(query, subject)
    inner_rng

    ## GRanges object with 2 ranges and 2 metadata columns:
    ##       seqnames    ranges strand |       key.a       key.b
    ##          <Rle> <IRanges>  <Rle> | <character> <character>
    ##   [1]     chr1       1-7      + |           a           A
    ##   [2]     chr1       1-7      + |           a           B
    ##   -------
    ##   seqinfo: 1 sequence from an unspecified genome; no seqlengths

Figure 3: Inner Join

We also provide a convenience method called `find_overlaps` that computes the same result as `join_overlap_inner()`.

    find_overlaps(query, subject)

    ## GRanges object with 2 ranges and 2 metadata columns:
    ##       seqnames    ranges strand |       key.a       key.b
    ##          <Rle> <IRanges>  <Rle> | <character> <character>
    ##   [1]     chr1       1-7      + |           a           A
    ##   [2]     chr1       1-7      + |           a           B
    ##   -------
    ##   seqinfo: 1 sequence from an unspecified genome; no seqlengths

The `join_overlap_left()` method will perform an outer left join.

First any overlaps that are found will be returned similar to `join_overlap_inner()`. Then any non-overlapping ranges will be returned, with missing values on the metadata columns.

    left_rng <- join_overlap_left(query, subject)
    left_rng

    ## GRanges object with 3 ranges and 2 metadata columns:
    ##       seqnames    ranges strand |       key.a       key.b
    ##          <Rle> <IRanges>  <Rle> | <character> <character>
    ##   [1]     chr1       1-7      + |           a           A
    ##   [2]     chr1       1-7      + |           a           B
    ##   [3]     chr1      9-10      - |           b        <NA>
    ##   -------
    ##   seqinfo: 1 sequence from an unspecified genome; no seqlengths

Figure 4: Left Join

Compared with `filter_by_overlaps()` above, the overlap left join expands the `Ranges` to give information about each interval on the query `Ranges` that overlap those on the subject `Ranges` as well as the intervals on the left that do not overlap any range on the right.

## 7.1 Finding your neighbours

We also provide methods for finding nearest, preceding or following `Ranges`. Conceptually this is identical to our approach for finding overlaps, except the semantics of the join are different.

    join_nearest(ir0, ir1)

    ## IRanges object with 4 ranges and 1 metadata column:
    ##           start       end     width |        gc
    ##       <integer> <integer> <integer> | <numeric>
    ##   [1]         5         9         5 |  0.780359
    ##   [2]        10        14         5 |  0.780359
    ##   [3]        15        19         5 |  0.780359
    ##   [4]        20        24         5 |  0.780359

    join_follow(ir0, ir1)

    ## IRanges object with 4 ranges and 1 metadata column:
    ##           start       end     width |        gc
    ##       <integer> <integer> <integer> | <numeric>
    ##   [1]         5         9         5 |  0.777584
    ##   [2]        10        14         5 |  0.603324
    ##   [3]        15        19         5 |  0.780359
    ##   [4]        20        24         5 |  0.780359

    join_precede(ir0, ir1) # nothing precedes returns empty `Ranges`

    ## IRanges object with 0 ranges and 1 metadata column:
    ##        start       end     width |        gc
    ##    <integer> <integer> <integer> | <numeric>

    join_precede(ir1, ir0)

    ## IRanges object with 5 ranges and 1 metadata column:
    ##           start       end     width |        gc
    ##       <integer> <integer> <integer> | <numeric>
    ##   [1]         2         4         3 |  0.777584
    ##   [2]         3         6         4 |  0.827303
    ##   [3]         4         8         5 |  0.603324
    ##   [4]         5        10         6 |  0.491232
    ##   [5]         6        12         7 |  0.780359

## 7.2 Example: dealing with multi-mapping

This example is taken from the Bioconductor support site.

We have two `Ranges` objects. The first contains single nucleotide positions corresponding to an intensity measurement such as a ChiP-seq experiment, while the other contains coordinates for two genes of interest.

We want to identify which positions in the `intensities` `Ranges` overlap the genes, where each row corresponds to a position that overlaps a single gene.

First we create the two `Ranges` objects

    intensities <- data.frame(seqnames = "VI",
                              start = c(3320:3321,3330:3331,3341:3342),
                              width = 1) %>%
      as_granges()

    intensities

    ## GRanges object with 6 ranges and 0 metadata columns:
    ##       seqnames    ranges strand
    ##          <Rle> <IRanges>  <Rle>
    ##   [1]       VI      3320      *
    ##   [2]       VI      3321      *
    ##   [3]       VI      3330      *
    ##   [4]       VI      3331      *
    ##   [5]       VI      3341      *
    ##   [6]       VI      3342      *
    ##   -------
    ##   seqinfo: 1 sequence from an unspecified genome; no seqlengths

    genes <- data.frame(seqnames = "VI",
                        start = c(3322, 3030),
                        end = c(3846, 3338),
                        gene_id=c("YFL064C", "YFL065C")) %>%
      as_granges()

    genes

    ## GRanges object with 2 ranges and 1 metadata column:
    ##       seqnames    ranges strand |     gene_id
    ##          <Rle> <IRanges>  <Rle> | <character>
    ##   [1]       VI 3322-3846      * |     YFL064C
    ##   [2]       VI 3030-3338      * |     YFL065C
    ##   -------
    ##   seqinfo: 1 sequence from an unspecified genome; no seqlengths

Now to find where the positions overlap each gene, we can perform an overlap join. This will automatically carry over the gene_id information as well as their coordinates (we can drop those by only selecting the gene_id).

    olap <- join_overlap_inner(intensities, genes) %>%
      select(gene_id)
    olap

    ## GRanges object with 8 ranges and 1 metadata column:
    ##       seqnames    ranges strand |     gene_id
    ##          <Rle> <IRanges>  <Rle> | <character>
    ##   [1]       VI      3320      * |     YFL065C
    ##   [2]       VI      3321      * |     YFL065C
    ##   [3]       VI      3330      * |     YFL065C
    ##   [4]       VI      3330      * |     YFL064C
    ##   [5]       VI      3331      * |     YFL065C
    ##   [6]       VI      3331      * |     YFL064C
    ##   [7]       VI      3341      * |     YFL064C
    ##   [8]       VI      3342      * |     YFL064C
    ##   -------
    ##   seqinfo: 1 sequence from an unspecified genome; no seqlengths

Several positions match to both genes. We can count them using `summarise` and grouping by the `start` position:

    olap %>%
      group_by(start) %>%
      summarise(n = n())

    ## DataFrame with 6 rows and 2 columns
    ##       start         n
    ##   <integer> <integer>
    ## 1      3320         1
    ## 2      3321         1
    ## 3      3330         2
    ## 4      3331         2
    ## 5      3341         1
    ## 6      3342         1

## 7.3 Grouping by overlaps

It’s also possible to group by overlaps. Using this approach we can count the number of overlaps that are greater than 0.

    grp_by_olap <- ir0 %>%
      group_by_overlaps(ir1)
    grp_by_olap

    ## IRanges object with 6 ranges and 2 metadata columns:
    ## Groups: query [2]
    ##           start       end     width |        gc     query
    ##       <integer> <integer> <integer> | <numeric> <integer>
    ##   [1]         5         9         5 |  0.827303         1
    ##   [2]         5         9         5 |  0.603324         1
    ##   [3]         5         9         5 |  0.491232         1
    ##   [4]         5         9         5 |  0.780359         1
    ##   [5]        10        14         5 |  0.491232         2
    ##   [6]        10        14         5 |  0.780359         2

    grp_by_olap %>%
      mutate(n_overlaps = n())

    ## IRanges object with 6 ranges and 3 metadata columns:
    ## Groups: query [2]
    ##           start       end     width |        gc     query n_overlaps
    ##       <integer> <integer> <integer> | <numeric> <integer>  <integer>
    ##   [1]         5         9         5 |  0.827303         1          4
    ##   [2]         5         9         5 |  0.603324         1          4
    ##   [3]         5         9         5 |  0.491232         1          4
    ##   [4]         5         9         5 |  0.780359         1          4
    ##   [5]        10        14         5 |  0.491232         2          2
    ##   [6]        10        14         5 |  0.780359         2          2

Of course we can also add overlap counts via the `count_overlaps()` function.

    ir0 %>%
      mutate(n_overlaps = count_overlaps(., ir1))

    ## IRanges object with 4 ranges and 1 metadata column:
    ##           start       end     width | n_overlaps
    ##       <integer> <integer> <integer> |  <integer>
    ##   [1]         5         9         5 |          4
    ##   [2]        10        14         5 |          2
    ##   [3]        15        19         5 |          0
    ##   [4]        20        24         5 |          0

# 8 Data Import/Output

We provide convenience functions via `rtracklayer` and `GenomicAlignments` for reading/writing the following data formats to/from `Ranges` objects.

`plyranges` functions | File Format
--- | ---
`read_bam()` | BAM
`read_bed()`/`write_bed()` | BED
`read_bed_graph()`/ `write_bed_graph()` | BEDGraph
`read_narrowpeaks()`/`write_narrowpeaks()` | narrowPeaks
`read_gff()` / `write_gff()` | GFF(1-3)/ GTF
`read_bigwig()` / `write_bigwig()` | BigWig
`read_wig()` /`write_wig()` | Wig

# 9 Learning more

There are many other resources and workshops available to learn to use `plyranges` and related Bioconductor packages, especially for more realistic analyses than the ones covered here:

- The fluentGenomics workflow package is an end-to-end workflow package for integrating differential expression results with differential accessibility results.
- The Bioc 2018 Workshop book has worked examples of using `plyranges` to analyse publicly available genomics data.
- The extended vignette in the plyrangesWorkshops package has a detailed walk through of using plyranges for coverage analysis.
- The case study by Michael Love using plyranges with tximeta to follow up on interesting hits from a combined RNA-seq and ATAC-seq analysis.
- The journal article (preprint here) has details about the overall philosophy and design of plyranges.

# 10 Appendix

    sessionInfo()

    ## R version 4.1.0 (2021-05-18)
    ## Platform: x86_64-pc-linux-gnu (64-bit)
    ## Running under: Ubuntu 20.04.2 LTS
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    ## BLAS:   /home/biocbuild/bbs-3.13-bioc/R/lib/libRblas.so
    ## LAPACK: /home/biocbuild/bbs-3.13-bioc/R/lib/libRlapack.so
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    ##  [9] LC_ADDRESS=C               LC_TELEPHONE=C
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    ##
    ## attached base packages:
    ## [1] stats4    parallel  stats     graphics  grDevices utils     datasets
    ## [8] methods   base
    ##
    ## other attached packages:
    ## [1] ggplot2_3.3.3        plyranges_1.12.0     GenomicRanges_1.44.0
    ## [4] GenomeInfoDb_1.28.0  IRanges_2.26.0       S4Vectors_0.30.0
    ## [7] BiocGenerics_0.38.0  BiocStyle_2.20.0
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    ##  [1] MatrixGenerics_1.4.0        Biobase_2.52.0
    ##  [3] sass_0.4.0                  jsonlite_1.7.2
    ##  [5] bslib_0.2.5.1               assertthat_0.2.1
    ##  [7] BiocManager_1.30.15         highr_0.9
    ##  [9] GenomeInfoDbData_1.2.6      Rsamtools_2.8.0
    ## [11] yaml_2.2.1                  pillar_1.6.1
    ## [13] lattice_0.20-44             glue_1.4.2
    ## [15] digest_0.6.27               XVector_0.32.0
    ## [17] colorspace_2.0-1            htmltools_0.5.1.1
    ## [19] Matrix_1.3-3                XML_3.99-0.6
    ## [21] pkgconfig_2.0.3             magick_2.7.2
    ## [23] bookdown_0.22               zlibbioc_1.38.0
    ## [25] purrr_0.3.4                 scales_1.1.1
    ## [27] BiocParallel_1.26.0         tibble_3.1.2
    ## [29] generics_0.1.0              farver_2.1.0
    ## [31] ellipsis_0.3.2              withr_2.4.2
    ## [33] SummarizedExperiment_1.22.0 magrittr_2.0.1
    ## [35] crayon_1.4.1                evaluate_0.14
    ## [37] fansi_0.4.2                 tools_4.1.0
    ## [39] BiocIO_1.2.0                lifecycle_1.0.0
    ## [41] matrixStats_0.58.0          stringr_1.4.0
    ## [43] munsell_0.5.0               DelayedArray_0.18.0
    ## [45] Biostrings_2.60.0           compiler_4.1.0
    ## [47] jquerylib_0.1.4             rlang_0.4.11
    ## [49] grid_4.1.0                  RCurl_1.98-1.3
    ## [51] rjson_0.2.20                bitops_1.0-7
    ## [53] labeling_0.4.2              rmarkdown_2.8
    ## [55] restfulr_0.0.13             gtable_0.3.0
    ## [57] DBI_1.1.1                   R6_2.5.0
    ## [59] GenomicAlignments_1.28.0    knitr_1.33
    ## [61] dplyr_1.0.6                 rtracklayer_1.52.0
    ## [63] utf8_1.2.1                  stringi_1.6.2
    ## [65] Rcpp_1.0.6                  vctrs_0.3.8
    ## [67] tidyselect_1.1.1            xfun_0.23