# Generate a scope for step.gam

### Description

Given a data.frame as an argument, generate a scope list for use in step.gam, each element of which gives the candidates for that term.

### Usage

1 |

### Arguments

`frame` |
a data.frame to be used in |

`response` |
The column in |

`smoother` |
which smoother to use for the nonlinear terms; i.e. "s" or "lo", or any other supplied smoother. Default is "s". |

`arg` |
a character (vector), which is the
argument to |

`form` |
if |

### Details

This function creates a similar scope formula for each variable in the
frame. A column named "x" by default will generate a scope term
`~1+x+s(x)`

. With `arg=c("df=4","df=6")`

we get `~1+x+s(x,df=4)+s(x,df=6)`

.
With form=FALSE, we would get the character vector `c("1","x","s(x,df=4)","s(x,df=6")`

.

### Value

a scope list is returned, with either a formula or a character vector for each term, whcih describes the candidates for that term in the gam.

### Author(s)

Written by Trevor Hastie, following closely the design in the
"Generalized Additive Models" chapter (Hastie, 1992) in Chambers and
Hastie (1992).
This version of `gam.scope`

is adapted from the S
version.

### References

Hastie, T. J. (1991)
*Generalized additive models.*
Chapter 7 of *Statistical Models in S*
eds J. M. Chambers and T. J. Hastie, Wadsworth \& Brooks/Cole.

### See Also

`step.gam`

### Examples

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