seqXtend(sfsmisc)
seqXtend()所属R语言包：sfsmisc
Sequence Covering the Range of X, including X
序列覆盖范围的X，其中X
译者：生物统计家园网 机器人LoveR
描述----------Description----------
Produce a sequence of unique values (sorted increasingly), containing the initial set of values x. This can be useful for setting prediction e.g. ranges in nonparametric regression.
产生一系列的唯一值（排序越来越多的），其中包含的初始设置值x。设置预测例如，这可能是有用的在非参数回归的范围。
用法----------Usage----------
seqXtend(x, length., method = c("simple", "aim", "interpolate"),
from = NULL, to = NULL)
参数----------Arguments----------
参数：x
numeric vector.
数字矢量。
参数：length.
integer specifying approximately the desired length() of the result.
整数，指定大约所需的length()的结果。
参数：method
string specifying the method to be used. The default, "simple" uses seq(*, length.out = length.) where "aim" aims a bit better towards the desired final length, and "interpolate" interpolates evenly inside each interval (x[i], x[i+1]) in a way to make all the new intervalls of approximately the same length.
字符串，指定要使用的方法。默认情况下，"simple"使用seq(*, length.out = length.)其中"aim"的目的是更好一点对所需的最终长度，和"interpolate"插值均匀地在每个时间间隔(x[i], x[i+1])的方式，以使所有的新的卷时间大致相同的长度。
参数：from, to
numbers to be passed to (the default method for) seq(), defaulting to the minimal and maximal x value, respectively.
数字被传递到（默认方法）seq()，默认的最小和最大的x这个值。
值----------Value----------
numeric vector of increasing values, of approximate length length. (unless length. < length(unique(x)) in which case, the result is simply sort(unique(x))), containing the original values of x.
数字矢量的增加值，长度大约length.（除非length. < length(unique(x))在这种情况下，结果是sort(unique(x))），包含原始值x。
From, r <- seqXtend(x, *), the original values are at indices ix <- match(x,r), i.e., identical(x, r[ix]).
从r <- seqXtend(x, *)，原来的值是在指数ix <- match(x,r)，即identical(x, r[ix])。
注意----------Note----------
method = "interpolate" typically gives the best results. Calling roundfixS, it also need more computational resources than the other methods.
method = "interpolate"通常给出了最好的结果。调用roundfixS，它比其他方法还需要更多的计算资源。
（作者）----------Author(s)----------
Martin Maechler
参见----------See Also----------
seq; plotDS can make particularly good use of seqXtend()
seqplotDS可以使用seqXtend()特别好
实例----------Examples----------
a <- c(1,2,10,12)
seqXtend(a, 12)# --> simply 1:12[ - >简单1:12]
seqXtend(a, 12, "interp")# ditto[同上]
seqXtend(a, 12, "aim")# really worse[真是雪上加霜]
stopifnot(all.equal(seqXtend(a, 12, "interp"), 1:12))
## for a "general" x, however, "aim" aims better than default[然而，编号为“一般”X“目的”的宗旨，比默认]
x <- c(1.2, 2.4, 4.6, 9.9)
length(print(seqXtend(x, 12))) # 14[14]
length(print(seqXtend(x, 12, "aim"))) # 12[12]
length(print(seqXtend(x, 12, "int"))) # 12[12]
## "interpolate" is really nice:[“插”是非常好的：]
xt <- seqXtend(x, 100, "interp")
plot(xt, main="seqXtend(*, 100, \"interpol\")")
points(match(x,xt), x, col = 2, pch = 20)
# .... you don't even see that it's not equidistant[....你甚至看不到它的不等距]
# whereas the cheap method shows ...[而廉价的方法，显示...]
xt2 <- seqXtend(x, 100)
plot(xt2, col="blue")
points(match(x,xt2), x, col = 2, pch = 20)
## with "Date" objects[＃“日期”对象]
Drng <- as.Date(c("2007-11-10", "2012-07-12"))
(px <- pretty(Drng, n = 16)) # say, for the main labels[说，主标签]
## say, a finer grid, for ticks -- should be almost equidistant[＃说，更精细的网格，刻度线 - 应该是几乎等距离]
n3 <- 3*length(px)
summary(as.numeric(diff(seqXtend(px, n3)))) # wildly varying[疯狂不同]
summary(as.numeric(diff(seqXtend(px, n3, "aim")))) # (ditto)[（同上）]
summary(as.numeric(diff(seqXtend(px, n3, "int")))) # around 30[约30]
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注：
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发表于 2012-9-30 01:41:33
