stepfun(stats)
stepfun()所属R语言包：stats
Step Function Class
阶跃函数类
译者：生物统计家园网 机器人LoveR
描述----------Description----------
Given the vectors (x[1], …, x[n]) and (y[0], y[1], …, y[n]) (one value more!), stepfun(x,y,...) returns an interpolating "step" function, say fn. I.e., fn(t) = c[i] (constant) for t in ( x[i], x[i+1]) and at the abscissa values, if (by default) right = FALSE, fn(x[i]) = y[i] and for right = TRUE, fn(x[i]) = y[i-1], for i=1, …, n.
鉴于向量(x[1], …, x[n])和(y[0], y[1], …, y[n])（一个值！），stepfun(x,y,...)返回插值的步骤“功能，说fn。即fn(t) = c“[i]（常量）t in ( x[i], x[i+1])”在横坐标值（默认），如果right = FALSE，fn(x[i]) = y[i]和right = TRUE fn(x[i]) = y[i-1]，i=1, …, n。
The value of the constant c[i] above depends on the "continuity" parameter f. For the default, right = FALSE, f = 0, fn is a cadlag function, i.e., continuous at right, limit ("the point") at left. In general, c[i] is interpolated in between the neighbouring y values, c[i] = (1-f)*y[i] + f*y[i+1]. Therefore, for non-0 values of f, fn may no longer be a proper step function, since it can be discontinuous from both sides, unless right = TRUE, f = 1 which is right-continuous.
不断c[i]以上的价值取决于“连续性”参数f。默认情况下，right = FALSE, f = 0，fn cadlag功能，即连续在右边，在左边的限制（“点”）。在一般情况下，c[i]插在邻近y值之间，c[i] = (1-f)*y[i] + f*y[i+1]。因此，非0值f，fn可能不再是一个正确的步骤功能，因为它可以从双方的不连续的，除非right = TRUE, f = 1这是右连续。
用法----------Usage----------
stepfun(x, y, f = as.numeric(right), ties = "ordered",
right = FALSE)
is.stepfun(x)
knots(Fn, ...)
as.stepfun(x, ...)
## S3 method for class 'stepfun'
print(x, digits = getOption("digits") - 2, ...)
## S3 method for class 'stepfun'
summary(object, ...)
参数----------Arguments----------
参数：x
numeric vector giving the knots or jump locations of the step function for stepfun(). For the other functions, x is as object below.
数字矢量疙瘩或stepfun()跳步功能的位置。对于其他功能，x是object下面。
参数：y
numeric vector one longer than x, giving the heights of the function values between the x values.
提供数字矢量一个较长的比x，x值之间的函数值的高度。
参数：f
a number between 0 and 1, indicating how interpolation outside the given x values should happen. See approxfun.
0和1之间的数，表示外界给定的x值的插值应发生。看到approxfun。
参数：ties
Handling of tied x values. Either a function or the string "ordered". See approxfun.
绑x值的处理。无论是功能或字符串"ordered"。看到approxfun。
参数：right
logical, indicating if the intervals should be closed on the right (and open on the left) or vice versa.
逻辑，表示如果时间间隔应关闭右侧（左侧开）或反之亦然。
参数：Fn, object
an R object inheriting from "stepfun".
从"stepfun"R对象继承。
参数：digits
number of significant digits to use, see print.
有效位数的号码使用，请参阅print。
参数：...
potentially further arguments (required by the generic).
（通用要求）可能进一步的论据。
值----------Value----------
A function of class "stepfun", say fn.
一个功能的类"stepfun"说fn。
There are methods available for summarizing ("summary(.)"), representing ("print(.)") and plotting ("plot(.)", see plot.stepfun) "stepfun" objects.
有方法可用于汇总（"summary(.)"），占（"print(.)"）和绘图（"plot(.)"，看到plot.stepfun）"stepfun"对象。
The environment of fn contains all the information needed;
environmentfn包含所需的所有信息;
参数："x","y"
the original arguments
原来的参数
参数："n"
number of knots (x values)
节数（X值）
参数："f"
continuity parameter
连续性参数
参数："yleft", "yright"
the function values outside the knots
函数值外结
参数："method"
(always == "constant", from approxfun(.)).
（总是== "constant"，approxfun(.)）。
The knots are also available via knots(fn).
也可通过knots(fn)疙瘩。
作者（S）----------Author(s)----------
Martin Maechler, <a href="mailto:maechler@stat.math.ethz.ch">maechler@stat.math.ethz.ch</a> with some basic
code from Thomas Lumley.
参见----------See Also----------
ecdf for empirical distribution functions as special step functions and plot.stepfun for plotting step functions.
ecdf特步功能和plot.stepfun绘制步骤职能的经验分布函数。
approxfun and splinefun.
approxfun和splinefun。
举例----------Examples----------
y0 <- c(1.,2.,4.,3.)
sfun0 <- stepfun(1:3, y0, f = 0)
sfun.2 <- stepfun(1:3, y0, f = .2)
sfun1 <- stepfun(1:3, y0, f = 1)
sfun1c <- stepfun(1:3, y0, right=TRUE)# hence f=1[因此f = 1]
sfun0
summary(sfun0)
summary(sfun.2)
## look at the internal structure:[＃看看内部结构：]
unclass(sfun0)
ls(envir = environment(sfun0))
x0 <- seq(0.5,3.5, by = 0.25)
rbind(x=x0, f.f0 = sfun0(x0), f.f02= sfun.2(x0),
f.f1 = sfun1(x0), f.f1c = sfun1c(x0))
## Identities :[＃身份：]
stopifnot(identical(y0[-1], sfun0 (1:3)),# right = FALSE[右为FALSE]
identical(y0[-4], sfun1c(1:3)))# right = TRUE[右= TRUE，]
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。
|
发表于 2012-2-16 19:46:12
