LeetCode //Bash - 194. Transpose File

194. Transpose File

Given a text file file.txt, transpose its content.

You may assume that each row has the same number of columns, and each field is separated by the ’ ’ character.
 

Example:

If file.txt has the following content:
name age
alice 21
ryan 30
Output the following:
name alice ryan
age 21 30

From: LeetCode
Link: 194. Transpose File

Solution:

Ideas:

1. Reading lines and columns: awk processes the file line by line. For each field in the line, it appends the field to the corresponding index in the transposed array.

2. Constructing the transposed lines: As we read each line, we concatenate the fields to build the transposed rows. The NR variable tracks the line number.

3. Printing the transposed result: After processing all lines (END block), we print each element of the transposed array.

Code:

# Read from the file file.txt and print its transposed content to stdout.

awk '
{
    for (i = 1; i <= NF; i++) {
        if (NR == 1) {
            transposed[i] = $i
        } else {
            transposed[i] = transposed[i] " " $i
        }
    }
}
END {
    for (i = 1; i <= NF; i++) {
        print transposed[i]
    }
}' file.txt