lassoPoints {iSEE} | R Documentation

## Find rows of data within a closed lasso

### Description

Identify the rows of a data.frame lying within a closed lasso polygon, analogous to `brushedPoints`.

### Usage

    lassoPoints(df, lasso)

### Arguments

`df` | A data.frame from which to select rows.
`lasso` | A list containing data from a lasso.

### Details

This function uses `in.out` from the mgcv package to identify points within a polygon. This involves a boundary crossing algorithm that may not be robust in the presence of complex polygons with intersecting edges.

### Value

A subset of rows from `df` with coordinates lying within `lasso`.

### Author(s)

Aaron Lun

### See Also

`brushedPoints`

### Examples

    lasso <- list(coord=rbind(c(0, 0), c(0.5, 0), c(0, 0.5), c(0, 0)),
        closed=TRUE, mapping=list(x="X", y="Y"))
    values <- data.frame(X=runif(100), Y=runif(100),
        row.names=sprintf("VALUE_%i", seq_len(100)))
    lassoPoints(values, lasso)

    # With faceting information:
    lasso <- list(coord=rbind(c(0, 0), c(0.5, 0), c(0, 0.5), c(0, 0)),
        panelvar1="A", panelvar2="B", closed=TRUE,
        mapping=list(x="X", y="Y",
        panelvar1="FacetRow", panelvar2="FacetColumn"))
    values <- data.frame(X=runif(100), Y=runif(100),
        FacetRow=sample(LETTERS[1:2], 100, replace=TRUE),
        FacetColumn=sample(LETTERS[1:4], 100, replace=TRUE),
        row.names=sprintf("VALUE_%i", seq_len(100)))
    lassoPoints(values, lasso)

[Package iSEE version 1.6.1 Index]