另一个向量中特定对象向量中的第二大值

Question

我有一个非常大的数据与投资者，公司和股票。每家公司都有多个投资者，我想从每个公司的投资者那里得到第四个向量，其中包含第二大股票的价值。因为我向最大的投资者展示了：

df$bigInv <- aggregate(df$InvShare ~ df$Company, df, max)

这是我的数据框架的一个例子：在这里输入图像描述

Answer 1

重现性数据

df <- data.frame(id = c(1, 2, 3, 4, 5, 6, 7, 8),
                 Investor.Name =  c("Shigeo Kageyama", 
                                    "Shigeo Kageyama", 
                                    "Arataka Reigen",   
                                    "Arataka Reigen",  
                                    "Ritsu Kageyama",   
                                    "Ritsu Kageyama",
                                    "Ritsu Kageyama",   
                                    "Tenga Onigawara"),
                 Company = c("Body Improvement Club",   
                             "Salt Middle School",   
                             "Spirits Consultation ", 
                             "Pepper Middle School",
                             "Tofu Spirits School", 
                             "Psycho Helmet Cult",
                             "Chess Club",  
                             "Lecture Club"),
                 InvShare = c(
                           0.45,
                           0.12, 
                           0.89, 
                           0.541, 
                           0.15, 
                           0.75, 
                           0.14, 
                           0.1))

df

# id   Investor.Name               Company InvShare
# 1  1 Shigeo Kageyama Body Improvement Club    0.450
# 2  2 Shigeo Kageyama    Salt Middle School    0.120
# 3  3  Arataka Reigen Spirits Consultation     0.890
# 4  4  Arataka Reigen  Pepper Middle School    0.541
# 5  5  Ritsu Kageyama   Tofu Spirits School    0.150
# 6  6  Ritsu Kageyama    Psycho Helmet Cult    0.750
# 7  7  Ritsu Kageyama            Chess Club    0.140
# 8  8 Tenga Onigawara          Lecture Club    0.100

下面的代码将给你每一家公司第二大投资者的名字。

#The second of the list of affiliation
second = function(x) {
  if (length(x) == 1)
    return(x)
  return(sort(x, decreasing = TRUE)[2])}

aggregate(x = list( InvShare =  df$InvShare),
          by= list(second_member =df$Investor.Name),
          FUN=second)

# second_member InvShare
# 1  Arataka Reigen    0.541
# 2  Ritsu Kageyama    0.150
# 3 Shigeo Kageyama    0.120
# 4 Tenga Onigawara    0.100

这就是你要找的吗？

编辑的

我刚意识到你想在你的data.frame上开第四篇专栏。以下几行就可以做到这一点：

df$second  <- ave(x = df$InvShare,  
                  by = df$Investor.Name, 
                  FUN = second)

df

# id   Investor.Name               Company InvShare second
# 1  1 Shigeo Kageyama Body Improvement Club    0.450  0.120
# 2  2 Shigeo Kageyama    Salt Middle School    0.120  0.120
# 3  3  Arataka Reigen Spirits Consultation     0.890  0.541
# 4  4  Arataka Reigen  Pepper Middle School    0.541  0.541
# 5  5  Ritsu Kageyama   Tofu Spirits School    0.150  0.150
# 6  6  Ritsu Kageyama    Psycho Helmet Cult    0.750  0.150
# 7  7  Ritsu Kageyama            Chess Club    0.140  0.150
# 8  8 Tenga Onigawara          Lecture Club    0.100  0.100