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我正在尝试使用 splitstackshape 包中的分层函数在 R 中进行分层抽样。我有四个阶层（标记为 1:4）。当设置 size = 1 时，它返回属于每个层的一行（太棒了！）。但是，我无法将样本量增加一。

我希望它选择 5 行：其中 4 行属于 1:4 地层，第五行属于第 1 层（在我的研究地点覆盖最多区域的地层）；理想情况下，这将在不替换的情况下完成，因此从第 1 层采样的第二行将与第一行不同。

设置 size = 1 - 1.99 总是从每个层返回 1 行（总共 4 个）。设置 size = 2 返回 8 行（每层 2 行）。

数据框

homer_join_strat<- structure(list(cluster = c(4L, 3L, 4L, 5L, 5L, 4L, 4L, 4L, 5L, 
5L, 5L, 1L, 1L, 1L, 1L, 3L, 1L, 1L, 1L, 5L, 1L, 1L, 5L, 4L, 4L, 
4L), waterbody = c("Homer", "Homer", "Homer", "Homer", "Homer", 
"Homer", "Homer", "Homer", "Homer", "Homer", "Homer", "Homer", 
"Homer", "Homer", "Homer", "Homer", "Homer", "Homer", "Homer", 
"Homer", "Homer", "Homer", "Homer", "Homer", "Homer", "Homer"
), transect_number = 1:26, BLG = c(75, 38.4204909284952, 77.634011090573, 
82.1917808219178, 119.341563786008, 22.5422667501565, 155.275381552754, 
81.1332904056665, 37.037037037037, 73.2824427480916, 71.608040201005, 
208.806818181818, 116.504854368932, 119.775421085465, 104.408352668213, 
117.391304347826, 12.0603015075377, 93.5593220338983, 166.795366795367, 
20, 91.566265060241, 70.8860759493671, 0, 44.8765893792072, 0, 
3.96563119629874), GSF = c(0, 6.4034151547492, 11.090573012939, 
16.4383561643836, 4.11522633744856, 0, 0, 0, 0, 4.58015267175573, 
0, 21.3068181818182, 0, 0, 6.96055684454756, 0, 0, 0, 0, 0, 0, 
0, 0, 0, 0, 0), LMB = c(51.3157894736842, 83.2443970117396, 73.9371534195933, 
71.2328767123288, 28.8065843621399, 37.5704445835942, 59.721300597213, 
38.6349001931745, 66.6666666666667, 77.8625954198473, 67.8391959798995, 
63.9204545454545, 46.6019417475728, 22.4578914535246, 6.96055684454756, 
13.0434782608696, 24.1206030150754, 40.6779661016949, 60.2316602316602, 
56, 28.9156626506024, 55.6962025316456, 20.2360876897133, 31.413612565445, 
0, 31.7250495703899), YLB = c(0, 0, 14.7874306839187, 0, 4.11522633744856, 
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4.63320463320463, 0, 0, 
0, 0, 0, 0, 0), BLC = c(7.89473684210526, 12.8068303094984, 7.39371534195933, 
10.958904109589, 0, 0, 3.9814200398142, 0, 3.7037037037037, 13.7404580152672, 
11.3065326633166, 12.7840909090909, 3.88349514563107, 3.74298190892077, 
0, 0, 0, 4.06779661016949, 0, 16, 9.63855421686747, 5.06329113924051, 
20.2360876897133, 22.4382946896036, 0, 7.93126239259749), WHC = c(0, 
0, 0, 0, 0, 0, 3.9814200398142, 0, 7.40740740740741, 0, 0, 0, 
0, 7.48596381784155, 0, 0, 0, 0, 0, 0, 0, 10.126582278481, 0, 
4.48765893792072, 0, 0), RSF = c(0, 0, 0, 0, 0, 0, 11.9442601194426, 
0, 0, 13.7404580152672, 0, 0, 0, 0, 0, 0, 0, 0, 27.7992277992278, 
0, 4.81927710843374, 0, 0, 4.48765893792072, 0, 0), CCF = c(0, 
0, 0, 0, 0, 0, 0, 0, 3.7037037037037, 0, 0, 0, 3.88349514563107, 
0, 0, 0, 0, 8.13559322033898, 0, 0, 0, 0, 0, 0, 0, 0), BLB = c(0, 
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 8.52272727272727, 0, 0, 0, 0, 0, 
0, 0, 0, 0, 0, 0, 0, 0, 0)), class = "data.frame", row.names = c(NA, 
-26L))

代码

stratified(homer_join_strat, "cluster",  size=.06)
stratified(homer_join_strat, "cluster",  size=.07)
stratified(homer_join_strat, "cluster",  size=.09)
stratified(homer_join_strat, "cluster",  size=2)

有没有人有使用此函数选择不等于或不是数据中层数倍数的行数的经验？

我可以通过分别设置 size = .06、.07、.09 来让它选择 1、2、3 行（按正方形区域的顺序）（为什么我认为 1-1.99 之间的数字会给我 5 行选择

提前致谢！

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1 回答 1

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从您正在使用的函数的文档中“如果大小是一个命名向量，该函数将检查向量的长度是否与组的数量匹配并且名称是否与组名称匹配” - 然后它继续提供您的问题所问的一个例子。

  DF <- data.frame(
  ID = 1:100,
  A = sample(c("AA", "BB", "CC", "DD", "EE"), 100, replace = TRUE),
  B = rnorm(100), C = abs(round(rnorm(100), digits=1)),
  D = sample(c("CA", "NY", "TX"), 100, replace = TRUE),
  E = sample(c("M", "F"), 100, replace = TRUE))

  stratified(DF, "D", c(CA = 5, NY = 3, TX = 2))
于 2021-12-02T01:49:49.457 回答