讀取標準輸入爲R

Question

我有一個結構類似這樣的文件：

123 

Jhon: NewYork, Boston, gainesville 

Mike: LosAngeles 

Almudena: Baltimore, SanDiego, Austin, Memphis 

Anna: Washington, Oklahoma, Nashville, Denver, Phenix, Tucson 

... 

依此類推，直到123名和高達每人50個城市。我想將文件讀入R中一個可用的表格，例如，具有123行和51列（名稱+最多50個城市）的表格。理想的情況是，桌子在沒有城市的情況下有空白空間（例如，與僅在美國的兩個城市中的人相對應的行將具有48個空白空間）。

另一個，更有用的選項也將是一個兩列表（或矩陣），兩列的形式爲

Name City 
Jhon NewYork 
Jhon Boston 
Jhon gainesville 
Mike LosAngeles 
... 

Answer 1

我不太確定是否有可用的函數。但是爲這個文件編寫導入程序並不難：

ll <- readLines("input.txt") 

## keep only lines with "name: cities" 
ll <- ll[grep(":", ll)] 

## split at ":" to divide in name and cities 
s <- strsplit(ll, ":") 

## split by "," to divide cities 
s <- lapply(s, function(x) { 
    return(cbind(x[1], strsplit(x[2], ",")[[1]])) 
}) 

## bind list of matrices to one matrix 
m <- do.call(rbind, s) 

## remove whitespace in front of the cities 
m[, 2] <- gsub("^\\s+", "", m[, 2]) 
m 

#  [,1]  [,2] 
# [1,] "Jhon"  "NewYork" 
# [2,] "Jhon"  "Boston" 
# [3,] "Jhon"  "gainesville" 
# [4,] "Mike"  "LosAngeles" 
# [5,] "Almudena" "Baltimore" 
# [6,] "Almudena" "SanDiego" 
# [7,] "Almudena" "Austin" 
# [8,] "Almudena" "Memphis" 
# [9,] "Anna"  "Washington" 
#[10,] "Anna"  "Oklahoma" 
#[11,] "Anna"  "Nashville" 
#[12,] "Anna"  "Denver" 
#[13,] "Anna"  "Phenix" 
#[14,] "Anna"  "Tucson"