如何使用两个规则从一个变量创建新变量

本文介绍了如何使用两个规则从一个变量创建新变量的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

希望能从一个变量中创建新变量。

I would appreciate any help to create new variables from one variable.

特别是，我需要帮助同时为每个 ID创建一行和 E 的各个列，其中 E 的每个新列（是， E1 ， E2 ， E3 ）包含值 ID 的每一行的 E 。我尝试这样做，融化，然后传播，但出现错误：

Specifically, I need help to simultaneously create one row per each ID and various columns of E, where each of the new columns of E, (that is, E1, E2, E3) contains the values of E for each row of ID. I tried doing this which melt followed by spread but I am getting the error:

错误：行（4、7、9），（1、3、6），（2、5、8）的标识符重复

Error: Duplicate identifiers for rows (4, 7, 9), (1, 3, 6), (2, 5, 8)

另外，我尝试了此处和此处，但这些对我而言不起作用，因为我需要能够为行（4，1，2），（（）创建行标识符 7，3，5）和（9，6，8）。也就是说，第（4、1、2）行的 E 应该命名为 E1 ，行（7、3、5）的E 应该命名为 E2 ， E 行（9、6、8）应该命名为 E3 ，依此类推。

Additionally, I tried the solutions discussed here and here but these did not work for my case because I need to be able to create row identifiers for rows (4, 1, 2), (7, 3, 5), and (9, 6, 8). That is, E for rows (4, 1, 2) should be named E1, E for rows (7, 3, 5) should be named E2, E for rows (9, 6, 8) should be named E3, and so on.

#data

dT<-structure(list(A = c("a1", "a2", "a1", "a1", "a2", "a1", "a1", "a2", "a1"), B = c("b2", "b2", "b2", "b1", "b2", "b2", "b1", "b2", "b1"), ID = c("3", "4", "3", "1", "4", "3", "1", "4", "1" ), E = c(0.621142094943352, 0.742109450696123, 0.39439152996948, 0.40694392882818, 0.779607277916503, 0.550579323666347, 0.352622183880119, 0.690660491345867, 0.23378944873769)), class = c("data.table", "data.frame"), row.names = c(NA, -9L))

＃我的尝试

A B ID E 1: a1 b2 3 0.6211421 2: a2 b2 4 0.7421095 3: a1 b2 3 0.3943915 4: a1 b1 1 0.4069439 5: a2 b2 4 0.7796073 6: a1 b2 3 0.5505793 7: a1 b1 1 0.3526222 8: a2 b2 4 0.6906605 9: a1 b1 1 0.2337894 aTempDF <- melt(dT, id.vars = c("A", "B", "ID")) ) A B ID variable value 1: a1 b2 3 E 0.6211421 2: a2 b2 4 E 0.7421095 3: a1 b2 3 E 0.3943915 4: a1 b1 1 E 0.4069439 5: a2 b2 4 E 0.7796073 6: a1 b2 3 E 0.5505793 7: a1 b1 1 E 0.3526222 8: a2 b2 4 E 0.6906605 9: a1 b1 1 E 0.2337894 aTempDF%>%spread(variable, value) Error: Duplicate identifiers for rows (4, 7, 9), (1, 3, 6), (2, 5, 8)

＃预期输出

A B ID E1 E2 E3 1: a1 b2 3 0.6211421 0.3943915 0.5505793 2: a2 b2 4 0.7421095 0.7796073 0.6906605 3: a1 b1 1 0.4069439 0.3526222 0.2337894

谢谢您的帮助。

推荐答案

您可以使用 data.table

You can use dcast from data.table

library(data.table) dcast(dT, A + B + ID ~ paste0("E", rowid(ID))) # A B ID E1 E2 E3 #1 a1 b1 1 0.4069439 0.3526222 0.2337894 #2 a1 b2 3 0.6211421 0.3943915 0.5505793 #3 a2 b2 4 0.7421095 0.7796073 0.6906605

您需要先创建正确的时间变量，即 rowid（ ID）。

You need to create the correct 'time variable' first which is what rowid(ID) does.