Function(rms)
Function()所属R语言包：rms
Compose an S Function to Compute X beta from a Fit
从飞度，撰写的S函数计算X测试版
译者：生物统计家园网 机器人LoveR
描述----------Description----------
Function is a class of functions for creating other S functions. Function.rms is the method for creating S functions to compute X beta, based on a model fitted with rms in effect. Like latex.rms, Function.rms simplifies restricted cubic spline functions and factors out terms in second-order interactions. Function.rms will not work for models that have third-order interactions involving restricted cubic splines. Function.cph is a particular method for handling fits from cph, for which an intercept (the negative of the centering constant) is added to the model. sascode is a function that takes an S function such as one created by Function and does most of the editing to turn the function definition into a fragment of SAS code for computing X beta from the fitted model, along with assignment statements that initialize predictors to reference values. perlcode similarly creates Perl code to evaluate a fitted regression model.
Function是一类函数用于创建其他S系列功能。 Function.rms的方法创建S函数来计算X测试版，一个模型的基础上配备rms的影响。 latex.rms，Function.rms简化了三次样条函数和因素限制了二阶相互作用。 Function.rms不会工作模式，有限制三次样条函数的三阶交互。 Function.cph是适合从cph，其中的截距（负的定心常数）被添加到模型中一个特定的方法，用于处理。 sascode是一个函数，它接受一个S的功能，如创建的Function的编辑把函数的定义SAS代码片段的拟合模型计算x测试，以及用赋值语句初始化的预测参考值。 perlcode同样，Perl代码评估拟合回归模型。
用法----------Usage----------
## S3 method for class 'rms'
Function(object, intercept=NULL,
digits=max(8, .Options$digits), ...)
## S3 method for class 'cph'
Function(object, intercept=-object$center, ...)
# Use result as fun(predictor1=value1, predictor2=value2, \dots)
sascode(object, file='', append=FALSE)
perlcode(object)
参数----------Arguments----------
参数：object
a fit created with rms in effect
一个合适的创建rms的影响
参数：intercept
an intercept value to use (not allowed to be specified to Function.cph). The intercept is usually retrieved from the regression coefficients automatically.
截距的值使用（不允许指定Function.cph）。截距通常是从回归系数自动检索。
参数：digits
number of significant digits to use for coefficients and knot locations
一些重要的数字系数和结位置
参数：file
name of a file in which to write the SAS code. Default is to write to standard output.
名的文件，在其中写的SAS代码。默认是输出到标准输出。
参数：append
set to TRUE to have sascode append code to an existing file named file.
设置为TRUEsascode代码附加到现有文件名为file。
参数：...
arguments to pass to Function.rms from Function.cph
参数传递给Function.rmsFunction.cph
值----------Value----------
Function returns an S-Plus function that can be invoked in any usual context. The function has one argument per predictor variable, and the default values of the predictors are set to adjust-to values (see datadist). Multiple predicted X beta values may be calculated by specifying vectors as arguments to the created function. All non-scalar argument values must have the same length. perlcode returns a character string with embedded newline characters.
Function返回一个S-Plus功能，可以在任何通常情况下调用。每个预测变量的函数有一个参数被设置为默认值的预测adjust-to值（见datadist）。多预测，通过指定所创建的函数的参数向量X beta值可以计算。所有非标量参数值必须具有相同的长度。 perlcode返回一个字符串，嵌入的换行符。
（作者）----------Author(s)----------
Frank Harrell, Jeremy Stephens, and Thomas Dupont<br>
Department of Biostatistics<br>
Vanderbilt University<br>
f.harrell@vanderbilt.edu
参见----------See Also----------
latex.rms, transcan, predict.rms, rms, rms.trans
latex.rms，transcan，predict.rms，rms，rms.trans
实例----------Examples----------
set.seed(1331)
x1 <- exp(rnorm(100))
x2 <- factor(sample(c('a','b'),100,rep=TRUE))
dd <- datadist(x1, x2)
options(datadist='dd')
y <- log(x1)^2+log(x1)*(x2=='b')+rnorm(100)/4
f <- ols(y ~ pol(log(x1),2)*x2)
f$coef
g <- Function(f, digits=5)
g
sascode(g)
cat(perlcode(g), '\n')
g()
g(x1=c(2,3), x2='b') #could omit x2 since b is default category[，可以省略X2因为b是默认类别]
predict(f, expand.grid(x1=c(2,3),x2='b'))
g8 <- Function(f) # default is 8 sig. digits[默认值是8信号。数字]
g8(x1=c(2,3), x2='b')
options(datadist=NULL)
## Not run: [＃不运行：]
# Make self-contained functions for computing survival probabilities[自足的生存概率计算功能]
# using a log-normal regression[使用一个log正常回归]
f <- psm(Surv(d.time, death) ~ rcs(age,4)*sex, dist='gaussian')
g <- Function(f)
surv <- Survival(f)
# Compute 2 and 5-year survival estimates for 50 year old male[计算2年和5年生存率估计为50岁的男性]
surv(c(2,5), g(age=50, sex='male'))
## End(Not run)[＃（不执行）]
转载请注明:出自 生物统计家园网(http://www.biostatistic.net)。
注：
注1：为了方便大家学习，本文档为生物统计家园网机器人LoveR翻译而成，仅供个人R语言学习参考使用，生物统计家园保留版权。
注2：由于是机器人自动翻译，难免有不准确之处，使用时仔细对照中、英文内容进行反复理解，可以帮助R语言的学习。
注3：如遇到不准确之处，请在本贴的后面进行回帖，我们会逐渐进行修订。
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发表于 2012-9-27 19:10:26
