findInterval(base)
findInterval()所属R语言包：base
Find Interval Numbers or Indices
查找区间数或指数
译者：生物统计家园网 机器人LoveR
描述----------Description----------
Find the indices of x in vec, where vec must be sorted (non-decreasingly); i.e., if i <- findInterval(x,v), we have v[i[j]] ≤ x[j] < v[i[j] + 1] where v[0] := - Inf, v[N+1] := + Inf, and N <- length(vec). At the two boundaries, the returned index may differ by 1, depending on the optional arguments rightmost.closed and all.inside.
xvec，其中vec必须排序（非少地）的指标，也就是说，如果i <- findInterval(x,v)，我们有v[i[j]] ≤ x[j] < v[i[j] + 1]其中v[0] := - Inf，v[N+1] := + Inf，N <- length(vec)。在两个边界，返回的索引可能会有所不同1，根据可选参数rightmost.closed和all.inside。
用法----------Usage----------
findInterval(x, vec, rightmost.closed = FALSE, all.inside = FALSE)
参数----------Arguments----------
参数：x
numeric.
数字。
参数：vec
numeric, sorted (weakly) increasingly, of length N, say.
数字，排序（弱）越来越长N，，说。
参数：rightmost.closed
logical; if true, the rightmost interval, vec[N-1] .. vec[N] is treated as closed, see below.
逻辑，如果属实，最右边的时间间隔，vec[N-1] .. vec[N]封闭治疗，见下文。
参数：all.inside
logical; if true, the returned indices are coerced into 1,...,N-1, i.e., 0 is mapped to 1 and N to N-1.
逻辑;如果属实，返回指数被迫进入1,...,N-1，即0映射到1和N的N-1的。
Details
详情----------Details----------
The function findInterval finds the index of one vector x in another, vec, where the latter must be non-decreasing. Where this is trivial, equivalent to apply( outer(x, vec, ">="), 1, sum), as a matter of fact, the internal algorithm uses interval search ensuring O(n * log(N)) complexity where n <- length(x) (and N <- length(vec)). For (almost) sorted x, it will be even faster, basically O(n).
功能findInterval找到指数x另外，vec，而后者必须非递减的一个向量。这是微不足道的，相当于apply( outer(x, vec, ">="), 1, sum)，事实上，内部算法使用间隔搜索确保O(n * log(N))复杂n <- length(x)（N <- length(vec)）。 （几乎）排序x，它会更快，基本上O(n)。
This is the same computation as for the empirical distribution function, and indeed, findInterval(t, sort(X)) is identical to n * Fn(t; X[1],..,X[n]) where Fn is the empirical distribution function of X[1],..,X[n].
这是相同的经验分布函数的计算，事实上，findInterval(t, sort(X))是相同的n * Fn(t; X[1],..,X[n])其中FnX[1],..,X[n]的经验分布函数。
When rightmost.closed = TRUE, the result for x[j] = vec[N] ( = max(vec)), is N - 1 as for all other values in the last interval.
当rightmost.closed = TRUE结果x[j] = vec[N]（ = max(vec)）N - 1在过去的时间间隔的所有其他值。
值----------Value----------
vector of length length(x) with values in 0:N (and NA) where N <- length(vec), or values coerced to 1 N-1) if and only if all.inside = TRUE (equivalently coercing all x values inside the intervals). Note that NAs are propagated from x, and Inf values are allowed in both x and vec.
向量的长度length(x)与0:N值（和NA），其中N <- length(vec)，或强迫1N-1)值，当且仅当all.inside = TRUE（等效强迫的时间间隔内的所有x值）。注意NA的传播，从x，允许在两个Inf x值和vec。
作者（S）----------Author(s)----------
Martin Maechler
参见----------See Also----------
approx(*, method = "constant") which is a generalization of findInterval(), ecdf for computing the empirical distribution function which is (up to a factor of n) also basically the same as findInterval(.).
approx(*, method = "constant")findInterval()，ecdf这是（高达因素的n）也基本相同的作为findInterval的（经验分布函数的计算。）这是一个概括。
举例----------Examples----------
N <- 100
X <- sort(round(stats::rt(N, df=2), 2))
tt <- c(-100, seq(-2,2, len=201), +100)
it <- findInterval(tt, X)
tt[it < 1 | it >= N] # only first and last are outside range(X)[只有第一个和最后一个以外的范围（X）]
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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。
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发表于 2012-2-17 10:07:25
