Question

How can I read any type of file from a location and access only a particular column to perform some operations on it. Some rows in my column may contain null values too.
Here’s an example:

name | age | sex
xyz  | 22  | F
yyy  | 25  | M
zzz  |     | F
aaa  | 22  | M

I want to access the column age so that I can perform some operations on it, like calculate age group, or performing some other task(s). I have written the code for this function but I still need to access the column to perform this.
I’m pretty new at file reading, hence I need help. I need to do this in java.

I have tried the following:

while (s.hasNextLine()) {
    String line = s.nextLine();
    System.out.println(line+"line ?????");
    String[] cols = line.split("|");
    System.out.println("lets see column only=="+cols[2]);
}

Yet my output is only the 2nd character of the 1st column.

Answer 1

I have tried

...
    String[] cols = line.split("|"); 
...

This doesn’t work since split takes a regular expression, and | is a special character when interpreted as a regular expression.

Instead, try

String[] cols = line.split("\\|");
                            ^^