awk - function to return permutations of n items out of m


 
Thread Tools Search this Thread
Top Forums Shell Programming and Scripting awk - function to return permutations of n items out of m
# 8  
Old 01-09-2019
Code:
echo {a..e}{a..e}{a..e} | xargs -n1

These 5 Users Gave Thanks to nezabudka For This Post:
# 9  
Old 01-09-2019
Quote:
Originally Posted by nezabudka
Code:
echo {a..e}{a..e}{a..e} | xargs -n1

nice idea, nezabudka.
Code:
echo {a..e}{a..e}{a..e} | xargs -n1| sed 's/./& /g'

This User Gave Thanks to vgersh99 For This Post:
# 10  
Old 01-09-2019
A very un-awk-like and more Perl-like script. Smilie

I added the sort routine because array iteration doesn't return the elements in order.
(Definitely not a good idea for large arrays.)

Note that the OP wants the results in an array for further processing in the same script.
I'm not sure how to retrieve the array elements in the order that they were inserted.
Maybe a forum member can suggest how to do so.

Code:
echo |
awk 'function generate_permutations(cs, item, n, k){
         if (k == 0){
             iter = iter + 1;
             arr[iter] = item;
             return;
         }
         for (i in cs){
             new_item = item""cs[i];
             generate_permutations(cs, new_item, n, k-1);
         }
     }
     {
          split("", arr, "");
          iter = 0;
          str = "a,b,c,d,e";
          n = split(str, charset, ",");
          k = 3;
          generate_permutations(charset, "", n, k);
          asort(arr);
          for (i=1; i <= iter; i++){
              printf "%s\n", arr[i];
          }
     }
    '


Last edited by durden_tyler; 01-09-2019 at 02:39 PM.. Reason: Too many blank lines added automatically between paragraphs.
This User Gave Thanks to durden_tyler For This Post:
# 11  
Old 01-09-2019
Quote:
Originally Posted by nezabudka
Code:
echo {a..e}{a..e}{a..e} | xargs -n1

SUPERB!

(Just one note for viewers though, this is NOT POSIX compliant...)

EDIT:
Modified to give spaces...

Code:
Last login: Wed Jan  9 19:12:39 on ttys000
AMIGA:amiga~> text=$( echo {a..e}_{a..e}_{a..e} | xargs -n1 ); echo "${text//_/ }"
a a a
a a b
a a c
a a d
. . .
e e e
AMIGA:amiga~> _


Last edited by wisecracker; 01-09-2019 at 03:17 PM.. Reason: No choice it will add to the bottom...
This User Gave Thanks to wisecracker For This Post:
# 12  
Old 01-09-2019
Quote:
Originally Posted by nezabudka
Code:
echo {a..e}{a..e}{a..e} | xargs -n1

Very good idea indeed. You won't need any externals doing it like this:

Code:
for p in {a..e}{a..e}{a..e} ; do
     echo "$x"
done

This works in bash as well as ksh93 but not in ksh88 and not in Bourne shell either.

bakunin
This User Gave Thanks to bakunin For This Post:
# 13  
Old 01-09-2019
Thank you all for an evaluation
Probably there should replace the heavyweight utility "xargs" and wrap everything in a function
like so
Code:
#!/bin/bash
prt() {
        str=$(seq -s"{$1..$2}" $3)
        eval echo ${str//[0-9]}
}
prt a e $((3+1)) | fmt -1 | sed 's/./& /g'

Or insert a loop "for in" as suggested above.
In ksh93 works too

Last edited by nezabudka; 01-09-2019 at 03:54 PM..
# 14  
Old 01-09-2019
Quote:
Originally Posted by nezabudka
Thank you all for an evaluation
Probably there should replace the heavyweight utility "xargs" and wrap everything in a function
like so
Code:
#!/bin/bash
prt() {
        str=$(seq -s"{$1..$2}" $3)
        eval echo ${str//[0-9]}
}
prt a e $((3+1)) | fmt -1 | sed 's/./& /g'

Or insert a loop "for in" as suggested above.
In ksh93 works too
Too many pipes and transient commands, (utilities)...
However $((3+1)) should be $((2+1)) or $((3)) on OSX 10.14.1, default bash terminal...
Code:
Last login: Wed Jan  9 19:58:11 on ttys000
AMIGA:amiga~> cd Desktop/Code/Shell
AMIGA:amiga~/Desktop/Code/Shell> bash --version
GNU bash, version 3.2.57(1)-release (x86_64-apple-darwin18)
Copyright (C) 2007 Free Software Foundation, Inc.
AMIGA:amiga~/Desktop/Code/Shell> ./abcde.sh
a a a 
a a b 
a a c 
a a d 
a a e 
a b a 
a b b 
a b c 
. . .
e d d 
e d e 
e e a 
e e b 
e e c 
e e d 
e e e 
AMIGA:amiga~/Desktop/Code/Shell> _

This User Gave Thanks to wisecracker For This Post:
Login or Register to Ask a Question

Previous Thread | Next Thread

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Function - Make your function return an exit status

Hi All, Good Day, seeking for your assistance on how to not perform my 2nd, 3rd,4th etc.. function if my 1st function is in else condition. #Body function1() { if then echo "exist" else echo "not exist" } #if not exist in function1 my all other function will not proceed.... (4 Replies)
Discussion started by: meister29
4 Replies

2. Shell Programming and Scripting

Return: can only `return' from a function or sourced script

Not sure where the problem is. I can run the script without any issue using the following command. . /opt/app/scripts/cdc_migration.sh But it fails with the below error when I try it this way /opt/app/scripts/cdc_migration.sh /opt/app/scripts/cdc_migration.sh: line 65: return: can only... (1 Reply)
Discussion started by: svajhala
1 Replies

3. Shell Programming and Scripting

awk permutations and combinations

hello, I'm reading this thread, in which there is this code :awk ' function comb(v,i) { for(i in A) { delete A; if(length(A)) comb((v?v"+":x)i) else print v"+"i A; } } { A } END { comb(); } ' infilebut I can't understand where does v come... (5 Replies)
Discussion started by: daPeach
5 Replies

4. UNIX for Dummies Questions & Answers

awk colon separated items

Hi, I need to filter my data based on items in column 23. Column 1 until column 23 are tab separated. This is how column 23 looks like: PRIMARY=<0/1:504:499,5:.:.:.:0.01:1:15:.> I want to extract lines if items 7 (separated by : ) in column 23 are more than 0.25 . In example above , item... (2 Replies)
Discussion started by: janshamsani
2 Replies

5. Shell Programming and Scripting

Permutations with awk

Hello I have a very simple input file in which there are a list of numbers: 1 2 3 4 5 6 7 8 9 10 My actual dataset is about 200 lines long. I was wondering how to add different permutations of 3 numbers for all the numbers in the dataset. For example: 1+2+3; 3+5+7; 2+8+1; 9+3+4... (1 Reply)
Discussion started by: Rabu
1 Replies

6. Shell Programming and Scripting

awk, help me - counting items and listing them

This is my first ever post... please help! :o I have two columns....here is part of the file... 12, 46798 6692, 46799 5710, ... (3 Replies)
Discussion started by: pelhabuan
3 Replies

7. Shell Programming and Scripting

Return a value from called function to the calling function

I have two scripts. script1.sh looks -------------------------------- #!/bin/bash display() { echo "Welcome to Unix" } display ----------------------------- Script2.sh #!/bin/bash sh script1.sh //simply calling script1.sh ------------------------------ (1 Reply)
Discussion started by: mvictorvijayan
1 Replies

8. Shell Programming and Scripting

awk between items including items

OS=HP-UX ksh The following works, except I want to include the <start> and <end> in the output. awk -F '<start>' 'BEGIN{RS="<end>"; OFS="\n"; ORS=""} {print $2} somefile.log' The following work in bash but not in ksh sed -n '/^<start>/,/^<end>/{/LABEL$/!p}' somefile.log (4 Replies)
Discussion started by: Ikon
4 Replies

9. Shell Programming and Scripting

Function's return value used inside awk

I have a file with the record of person: cat > $TMP/record.txt John Torres M Single 102353 Address Mark Santos M Maried 103001 Address Carla Maria F Maried 125653 Address #!/bin/ksh ManipulateID(){ ... return 0; ... #or return 1; } cat $TMP/record.txt | awk 'BEGIN {printf... (4 Replies)
Discussion started by: Orbix
4 Replies

10. Shell Programming and Scripting

Return an array of strings from user defined function in awk

Hello Friends, Is it possible to return an array from a user defined function in awk ? example: gawk ' BEGIN{} { catch_line = my_function(i) print catch_line print catch_line print catch_line } function my_function(i) { print "echo" line= "awk" line= "gawk"... (2 Replies)
Discussion started by: user_prady
2 Replies
Login or Register to Ask a Question