Scan and Read Data from a File in R Programming – scan() Function

scan() function in R Language is used to scan and read data. It is usually used to read data into vector or list or from file in R Language.

Syntax:
scan(“data.txt”, what = “character”)

Parameter:
data.txt: Text file to be scanned

Returns: Scanned output

Example 1: Scanning of Text

# R Program to scan a file

# Create example data.frame
data <- data.frame(x1 = c(1, 2, 2, 3),
                   x2 = c(4, 5, 6, 7),
                   x3 = c(8, 9, 10, 11))
data

# Write data as txt file to directory
write.table(data,
            file = "data.txt",
            row.names = FALSE)

# Get currently used directory
getwd()

# Apply scan function to txt file
data <- scan("data.txt", what = "character")
data

Output :

  x1 x2 x3
1  1  4  8
2  2  5  9
3  2  6 10
4  3  7 11

[1] "/home/cg/root/8121844"

[1] "x1" "x2" "x3" "1"  "4"  "8"  "2"  "5"  "9"  "2"  "6"  "10" "3"  "7"  "11"
Read 15 items

Example 2: Scan data as text

# R Program to scan a file

# Create example data.frame
data <- data.frame(x1 = c(1, 2, 2, 3),
                   x2 = c(4, 5, 6, 7),
                   x3 = c(8, 9, 10, 11))
data

# Write data as txt file to directory
write.table(data,
            file = "data.txt",
            row.names = FALSE)

# Read txt file into list
data <- scan("data.txt", what = list("", "", ""))
data

Output:

  x1 x2 x3
1  1  4  8
2  2  5  9
3  2  6 10
4  3  7 11
[[1]]
[1] "x1" "1"  "2"  "2"  "3" 

[[2]]
[1] "x2" "4"  "5"  "6"  "7" 

[[3]]
[1] "x3" "8"  "9"  "10" "11"

Read 5 records

Example 3: Skip lines with scan function

# R Program to scan a file

# Create example data.frame
data <- data.frame(x1 = c(1, 2, 2, 3),
                   x2 = c(4, 5, 6, 7),
                   x3 = c(8, 9, 10, 11))
data

# Write data as txt file to directory
write.table(data,
            file = "data.txt",
            row.names = FALSE)

# Skip first line of txt file
data <- scan("data.txt", skip = 1)
data

Output:

  x1 x2 x3
1  1  4  8
2  2  5  9
3  2  6 10
4  3  7 11
 [1]  1  4  8  2  5  9  2  6 10  3  7 11
Read 12 items

Example 4: Scan Excel CSV File

# R Program to scan a file

# Create example data.frame
data <- data.frame(x1 = c(1, 2, 2, 3),
                   x2 = c(4, 5, 6, 7),
                   x3 = c(8, 9, 10, 11))
data

# Write data as csv file to directory
write.table(data,
            file = "data.csv",
            row.names = FALSE)

# Apply scan function to csv file
data <- scan("data.csv", what = "character")
data

Output:

  x1 x2 x3
  x1 x2 x3
1  1  4  8
2  2  5  9
3  2  6 10
4  3  7 11
Read 15 items
 [1] "x1" "x2" "x3" "1"  "4"  "8"  "2"  "5"  "9"  "2"  "6"  "10" "3"  "7"  "11"

Example 5: Read input from the keyboard.

# take input from keyboard
z <- scan()
1
2
3
4

# print output on the screen
print(z)

Output:

Read 4 items
[1] 1 2 3 4

Here, in the above code, the scan() function will take input from the user and print value using the print() function.