extract specific columns from dataset using AWK

Question

I am trying to apply simple awk script to the dataset file. The file has 150 columns, I need cols between 20 to 30 only.

below is the script I used to get the records with field between 20 to 30.

code

BEGIN{}
{
for(f=20;f<=30;f++){
    print $f;
    }
}

I dont know why I get each value of the 10 fields in next line.

That is,

sample dataset

1 2 3 4 5 6 7
2 2 3 4 5 6 7 
3 3 3 4 5 6 7
4 4 4 4 5 6 7
5 5 5 5 5 6 7
6 6 6 6 6 6 7
7 7 7 7 7 7 7

I get output as 
1
2
3
4
5
6
7
2
2
3
4
5
6
7
...so on

Answer 1

Solution

BEGIN{FS=" ";}
{
for(f=20;f<=30;f++){
    printf("%s ",$f);
    }print "";
}

Answer 2

Below is another way of doing the same

awk -v f=20 -v t=30 '{for(i=f;i<=t;i++) \
                     printf("%s%s",$i,(i==t)?"\n":OFS)}' file

Notes

1. f and t are the starting and the ending columns respectively.
2. We used the ternary operator to control the field separator between the needed columns.

---

Edit

If you need columns 20 thru 30 and the last column , below would suffice :

awk -v f=20 -v t=30 '{for(i=f;i<=t;i++) \
                         printf("%s%s",$i,(i==t)?OFS""$NF"\n":OFS)}' file