R：在基于多列的数据框中使用排序功能

Question

我是一名心脏病专家，喜欢用 R 编写代码 - 我在对数据框进行排序时遇到了一个真正的问题，我怀疑解决方案真的很简单！

我有一个数据框，其中包含多项研究 df$study 的汇总值。大多数研究只有一个汇总值 (df$summary)。然而，正如您所见，研究 A 具有三个汇总值 (df$no.of.estimate)。见下文

study <- c("E", "A", "F", "A", "B", "A", "C", "D")
no.of.estimate <- c(1, 2, 1, 3, 1, 1, 1, 1)
summary <- c(1, 2, 3, 5, 6 ,7 ,8 ,9)
df <- data.frame(study, no.of.estimate, summary)

所以我想按 df$summary 对数据框进行排序 - 这很容易。但是，如果每项研究都有多个估计，那么我想将这些研究组合在一起并使用 "no.of.estimates" 列按顺序显示。

所以基本上所需的输出是

study <- c("E", "A", "A", "A", "F", "B", "C", "D")
no.of.estimate <- c(1, 1, 2, 3, 1, 1, 1, 1)
summary <- c(1, 7, 2, 5, 3 ,6 ,8 ,9)
df <- data.frame(study, no.of.estimate, summary)

Answer 1

你可以试试

library(dplyr)
df %>% 
     mutate(study=factor(study, levels=unique(study))) %>%
     arrange(study,no.of.estimate)
  #  study no.of.estimate summary
  #1     E              1       1
  #2     A              1       7
  #3     A              2       2
  #4     A              3       5
  #5     F              1       3
  #6     B              1       6
  #7     C              1       8
  #8     D              1       9

或base R方法

df$study <- factor(df$study, levels=unique(df$study))
df[with(df, order(study, no.of.estimate)), ]

数据

df <- structure(list(study = structure(c(5L, 1L, 6L, 1L, 2L, 1L, 3L, 
4L), .Label = c("A", "B", "C", "D", "E", "F"), class = "factor"), 
no.of.estimate = c(1, 2, 1, 3, 1, 1, 1, 1), summary = c(1, 
2, 3, 5, 6, 7, 8, 9)), .Names = c("study", "no.of.estimate", 
"summary"), row.names = c(NA, -8L), class = "data.frame")

预期的数据集是

df1 <- structure(list(study = structure(c(5L, 1L, 1L, 1L, 6L, 2L, 3L, 
4L), .Label = c("A", "B", "C", "D", "E", "F"), class = "factor"), 
no.of.estimate = c(1, 1, 2, 3, 1, 1, 1, 1), summary = c(1, 
7, 2, 5, 3, 6, 8, 9)), .Names = c("study", "no.of.estimate", 
"summary"), row.names = c(NA, -8L), class = "data.frame")

Answer 2

这是我的 data.table 尝试，同时保留您的列并创建新索引（尽管请先查看我的评论）。主要优点是您将通过引用更新数据集而不是创建新副本

library(data.table)
setorder(setDT(df)[, indx := .GRP, study], indx, no.of.estimate)[]
#    study no.of.estimate summary indx
# 1:     E              1       1    1
# 2:     A              1       7    2
# 3:     A              2       2    2
# 4:     A              3       5    2
# 5:     F              1       3    3
# 6:     B              1       6    4
# 7:     C              1       8    5
# 8:     D              1       9    6

R：在基于多列的数据框中使用排序功能

R: Using the sort function in a dataframe based on multiple columns

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