How can I read the header but also skip lines - read.table()?

Question

Data.txt:

Index;Time;
1;2345;
2;1423;
3;5123;

The code:

dat <- read.table('data.txt', skip = 1, nrows = 2, header =TRUE, sep =';')

The result:

  X1 X2345
1  2  1423
2  3  5123

I expect the header to be Index and Time, as follows:

  Index Time
1   2   1423
2   3   5123

How do I do that?

Solution 1

I am afraid, that there is no direct way to achieve this. Either you read the entire table and remove afterwards the lines you don't want or you read in the table twice and assign the header later:

header <- read.table('data.txt', nrows = 1, header = FALSE, sep =';', stringsAsFactors = FALSE)
dat    <- read.table('data.txt', skip = 2, header = FALSE, sep =';')
colnames( dat ) <- unlist(header)

Solution 2

You're using skip incorrectly. Try this:

dat <- read.table('data.txt', nrows = 2, header =TRUE, sep =';')[-1, ]

Solution 3

The solution using fread from data.table.

require(data.table)
fread("Data.txt", drop = "V3")[-1]

Result:

> fread("Data.txt", drop = "V3")[-1]
   Index Time
1:     2 1423
2:     3 5123

Solution 4

Instead of read.table(), use a readr function such as read_csv(), piped to dplyr::slice().

library(readr)
library(dplyr)
dat <- read_csv("data.txt") %>% slice(-1)

It's very fast too.

Solution 5

You could (in most cases), sub out the ending ; write a new file without the second row (which is really the first row because of the header), and use read.csv instead of read.table

> txt <- "Index;Time;
  1;2345;
  2;1423;
  3;5123;" 
> writeLines(sub(";$", "", readLines(textConnection(txt))[-2]), 'newTxt.txt')
> read.csv('newTxt.txt', sep = ";")
##   Index Time
## 1     2 1423
## 2     3 5123

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