如何将多列数据显示为单列答案

【问题标题】：How to display multiple columns data into single column如何将多列数据显示为单列
【发布时间】：2017-11-21 12:37:34
【问题描述】：

我的数据格式如下：

Parameter Value Parameter Value Parameter Value
Speed     100   Time      1     Distance  260

我想以表格格式将其显示为一列中的所有“参数”和另一列中的所有“值”

Parameter Value
Speed     100
Time       1
Distance  260

请帮帮我。

提前谢谢..!!

【问题讨论】：

data.frame(parameter = unlist(df1[c(TRUE, FALSE)]), value = unlist(df1[c(FALSE, TRUE)])) 或使用library(data.table); melt(setDT(df), measure = patterns("^Parameter", "^Value"), value.name = c('Parameter', 'Value'))[, variable := NULL][]

标签： r rscript

【解决方案1】：

这是一个快速而肮脏的解决方案。我假设列数是偶数。

library(tidyverse)
library(magrittr)
library(janitor) # For making column names unique.

# Create your example dataset.
test = c('Speed', 100, 'Time', 1, 'Distance', 260) %>%
  t() %>%
  as.tibble() %>%
  clean_names() # Make column names unique. tidyverse functions won't work otherwise.

# If you're reading your dataset into R via read_csv(), read_excel(), etc, be sure to
# run the imported tibble through clean_names().

# Create empty list to house each parameter and its value in each element.
params = list()

# Loop through the 'test' tibble, grabbing each parameter-value pair 
# and throwing them in their own element of the list 'params'
for (i in 1:(ncol(test)/2)) {

  # The 1st & 2nd columns are a parameter-value pair. Grab them.
  params[[i]] = select(test, 1:2)

  # Drop the 1st and second columns.
  test = select(test, -(1:2))

}

# We want to combine the tibbles in 'params' row-wise into one big tibble.
# First, the column names must be the same for each tibble.
params = lapply(X = params, FUN = setNames, c('v1', 'v2')) 

# Combine the tibbles row-wise into one big tibble.
test2 = do.call(rbind, params) %>%
  set_colnames(c('Parameter', 'Value'))

# End. 'test2' is the desired output.

【讨论】：

【解决方案2】：

@Namrata 是一种使用基本 R 函数的方法，不需要清理列名。

 rawData <- "Parameter Value Parameter Value Parameter Value
 Speed     100   Time      1     Distance  260"

 # read the data and convert to a matrix of character values
 # read the first row as data, not variable names
 theData <- as.matrix(read.table(textConnection(rawData),header=FALSE,
                      stringsAsFactors=FALSE))
 # transpose so required data is in second column
 transposedData <- t(theData)
 # calculate indexes to extract parameter names (odd) and values (even) rows
 # from column 2
 parmIndex <- seq(from=1,to=nrow(transposedData)-1,by=2)
 valueIndex <- seq(from=2,to=nrow(transposedData),by=2)
 # create 2 vectors 
 parameter <- transposedData[parmIndex,2]
 value <- transposedData[valueIndex,2]
 # convert to data frame and reset rownames 
 resultData <- data.frame(parameter,value=as.numeric(value),stringsAsFactors=FALSE)
 rownames(resultData) <- 1:nrow(resultData)

结果输出是：

问候，

镜头

【讨论】：