R: convert roll call matrix to series of vectors

vectorRepresentation {pscl} | R Documentation

## convert roll call matrix to series of vectors

### Description

Extract the information in a roll call matrix as a series of vectors with voting decision, a unique identifier for the legislator and a unique identifier for the roll call.

### Usage

    vectorRepresentation(object, dropList = list(codes = c("missing", "notInLegis")))

### Arguments

`object` | an object of class `rollcall`
`dropList` | a `dropList`; see `dropRollCall`

### Details

It is often the case that roll call matrices are sparse, say, when the roll call matrix has an “overlapping generations” structure; e.g., consider forming data by pooling across a long temporal sequence of legislatures such that relatively few of the legislators in the data set actually vote on any given roll call. In such a case, representing the data as a roll call matrix is not particularly helpful nor efficient, either for data summaries or modeling.

### Value

A `matrix` with `z` rows, where `z` is the number of non-missing entries in `object$votes`, with ‘missingness’ defined by the `codes` component of the `dropList`. The matrix has 3 columns:

`vote` | the voting decision, either a `1` if the corresponding element of the roll call matrix `object$votes` is in the `yea` component of `object$codes`, or a `0` if the corresponding element of the roll call matrix is in the `nay` component of `object$codes`. Non-missing entries of the roll call matrix are not stored.
`i` | the row of the roll call matrix `object$votes` that supplied the voting decision; i.e., a unique identifier for the legislator generating this `vote`
`j` | the column of the roll call matrix `object$votes` that supplied the `vote`; i.e., a unique identifier for the vote.

### Author(s)

Simon Jackman simon.jackman@sydney.edu.au

### See Also

`rollcall`

### Examples

    data(s109)
    y <- vectorRepresentation(s109)
    apply(y,2,table,exclude=NULL)

[Package pscl version 1.5.2 Index]