fp: Fielding Percentage
In peterxeno/sabermetrics-package: Sabermetrics Functions for Baseball Analytics

Description Usage Arguments Details Value Note Author(s) References Examples

A measure that reflects the percentage of times a player successfully handles a batted or thrown ball.

1	fp(po, a, e)

`po`	Putouts
`a`	Assists
`e`	Errors

Fielding percentage is not a particularly sought after defensive metric, especially with the advent of more comprehensive metrics such as UZR and DRS.

Returns a value equal to (po+a)/(po+a+e)

Fielding percentage is misleading in the fact that it does not account for a player's range – that is, if a player that cannot get to a ball gives up a hit instead of having an opportunity to make an out or error.

Fernando Crema, Peter Xenopoulos

https://en.wikipedia.org/wiki/Fielding_percentage

## Let's calculate Mike Trout's fielding percentage for 2014
## He had PO = 383, A = 4, E = 3
## We should get an output of .992
fp(383,4,3)

## The function is currently defined as
function (po, a, e) 
{
    fp <- (po + a)/(po + a + e)
    return(fp)
  }