使用數據框中的行值來選擇第二個數據框中的列

Question

所以我有兩個數據框......其中一個是一個寬格式，列名是日期，日期下列出了那些日子發生的所有問題。第二個數據幀是一個有多種列描繪的事物等信息that've發生在那一天..就像這樣：

df_1 <- 2017-07-15  2017-08-15  2017-09-15  2017-10-15 
     'crashed'   'crashed'  'reset'   'crashed' 
     'damaged'   'reset'   'reset'   'reset' 
     'no problems'  'crashed'  'crashed'   'reset' 

df_2 <- Date    Make   Model   Color 
     2017-07-15   iPhone   7    black 
     2017-08-15   Android  Galaxy   silver 
     2017-09-15   iPhone   6    white 
     2017-10-15  Blackberry  Curve    black 

我要訪問df_1的列誰的所有數據名稱與df_2的日期相匹配...原因是因爲我試圖使用來自df_2的信息作爲ggplot geom_point()，並在光標懸停在同一日期的某個點上時在工具提示中顯示來自df_1的信息

（下面的代碼是從這裏取的，只是輸入我的數據幀）： https://gitlab.com/snippets/16220

library("shiny") 
library("ggplot2") 

ui <- pageWithSidebar(
    headerPanel("Tooltips in ggplot2 + shiny"), 

    sidebarPanel(
HTML("Tooltips are managed by combination of shiny+ggplot hover functionality", 
    "and css styles. By setting hover argument of 'plotOutput' we could access", 
    "hover data from the server side, as an ordinary input. Hover input is", 
    "a list with: position of cursor ON the image; domain - that is", 
    "values of variables at the plotting area edges; range - that is position", 
    "of plotting area edges in pixels relative to whole image element.", 
    "Additionally for ggplot used mappings are returned. </br>", 
    "To create tooltip first we need to identify position of the cursor", 
    "inside the image element. We do it by calculating distances from left and", 
    "top edge of image element from hover data. Then we create tooltip, in this", 
    "app it is 'wellPanel' with some info inside, and set 'position' property", 
    "to 'absolute' and set 'left' and 'top' properties to calculated values.", 
    "However, 'absolute' position is defined as relative to the nearest positioned", 
    "ancestor. Because we want to position tooltip inside the image, we need", 
    "to put both 'plotOutput' with image and 'uiOutput' with tooltip content", 
    "inside additional 'div' element with 'position' property set to 'relative'.", 
    "We don't set top, left etc. for this element, so the actual position of", 
    "the image doesn't change - it's edges are identical as previously, so", 
    "we can use 'div' (for positioning tooltip) as substitute for image. </br>"), 
width = 3 
), 

mainPanel(

# this is an extra div used ONLY to create positioned ancestor for tooltip 
# we don't change its position 
div(
    style = "position:relative", 
    plotOutput("scatterplot", 
      hover = hoverOpts("plot_hover", delay = 100, delayType = "debounce")), 
    uiOutput("hover_info") 
), 
width = 7 
) 
) 

server <- function(input, output) { 

    output$scatterplot <- renderPlot({ 
    ggplot(df_2, aes(x = Date, y = make)) + 
     geom_point() 
    }) 


    output$hover_info <- renderUI({ 
hover <- input$plot_hover 
point <- nearPoints(df_2, hover, threshold = 5, maxpoints = 1, addDist = TRUE) 
if (nrow(point) == 0) return(NULL) 

# calculate point position INSIDE the image as percent of total dimensions 
# from left (horizontal) and from top (vertical) 
left_pct <- (hover$x - hover$domain$left)/(hover$domain$right - hover$domain$left) 
top_pct <- (hover$domain$top - hover$y)/(hover$domain$top - hover$domain$bottom) 

# calculate distance from left and bottom side of the picture in pixels 
left_px <- hover$range$left + left_pct * (hover$range$right - hover$range$left) 
top_px <- hover$range$top + top_pct * (hover$range$bottom - hover$range$top) 

# create style property fot tooltip 
# background color is set so tooltip is a bit transparent 
# z-index is set so we are sure are tooltip will be on top 
style <- paste0("position:absolute; z-index:100; background-color: rgba(245, 245, 245, 0.85); ", 
       "left:", left_px + 2, "px; top:", top_px + 2, "px;") 

# actual tooltip created as wellPanel 
wellPanel(
    style = style, 
    p(HTML(paste0(DF_1 DATE THAT MATCHES DF_2 DATE))) 
    ) 
    }) 
} 

runApp(list(ui = ui, server = server)) 

Answer 1

所以這裏確定是我的解決辦法，這ALTH ough可能不是最好的？似乎是我能做的唯一能夠得到我想要的東西。感謝MOODY_MUDSKIPPER的啓動點！

 df_1 %>% 
      mutate(variable = letters[1:n()]) 
     df_1 <- melt(df_1, id.vars='variable') 
     colnames(df_1)[2] <- "Date" #because the newly created variable column and the column with the dates were both named 'variable'... 
     df_1 <- dcast(df_1, Date ~ variable) 

     df_2 <- cbind(df_2,df_1,[,-1]) #subsetting to remove the first column from df_1 so that there arent two columns with Dates in them 

現在df_2將所有的信息，從它

Answer 2

這會適合你嗎？

數據

df_1 <- read.table(text="2017-07-15  2017-08-15  2017-09-15  2017-10-15 
'crashed'   'crashed'  'reset'   'crashed' 
'damaged'   'reset'   'reset'   'reset' 
'no problems'  'crashed'  'crashed'   'reset'",header=TRUE,stringsAsFactors = FALSE) 

df_2 <- read.table(text="Date    Make   Model   Color 
2017-07-15   iPhone   7    black 
2017-08-15   Android  Galaxy   silver 
2017-09-15   iPhone   6    white 
2017-10-15  Blackberry  Curve    black",header=TRUE,stringsAsFactors = FALSE) 

代碼

library(dplyr) 
library(tidyr) 
df_1 %>% 
    mutate(variable = letters[1:n()]) %>% 
    gather(Date, val, 1:4) %>% 
    mutate(Date = gsub("\\.","-",substr(Date,2,nchar(Date)))) %>% # you may not have to do this with your actual data 
    rbind(df_2 %>% gather(variable,val,-1)) %>% 
    spread(Date,val) 

結果

# variable 2017-07-15 2017-08-15 2017-09-15 2017-10-15 
# 1  a  crashed crashed  reset crashed 
# 2  b  damaged  reset  reset  reset 
# 3  c no problems crashed crashed  reset 
# 4 Color  black  silver  white  black 
# 5  Make  iPhone Android  iPhone Blackberry 
# 6 Model   7  Galaxy   6  Curve