Full Discussion: awk matrix problem
awk matrix problem Post 302337327 by Ygor on Thursday 23rd of July 2009 10:13:10 PM
07-24-2009
Try... Note that output is not sorted...
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## need help-matrix inverse (awk)

I have few days to complete my awk homework. But I'm stucked. i hope some1 will help me out. I have to inverse n x n matrix, but I have problems with finding the determinant of the matrix. I found the algoritm, how to find a determinant of n x n matrix:...

## matrix inverse (awk)

I need to inverse a matrix given in a file. The problem is I'm stuck with writing determinant finding algoritm into code. I found this algoritm about finding determinant of nxn matrix. This is what i need: Matrices and Determinants and here: a11 a12 a13 a21 a22 a23 a31 a32 a33...

## Perl- matrix problem

A C G T - A 5 -4 -4 -4 -5 C -4 5 -4 -4 -5 G -4 -4 5 -4 -5 T -4 -4 -4 5 -5 - -5 -5 -5 -5 0 So lets say I have a matrix which looks something like (above). Its basically a scoring matrix. the numbers are...

## awk? adjacency matrix to adjacency list / correlation matrix to list

Hi everyone I am very new at awk but think that that might be the best strategy for this. I have a matrix very similar to a correlation matrix and in practical terms I need to convert it into a list containing the values from the matrix (one value per line) with the first field of the line (row...

## Summing up a matrix using awk

Hi there, If anyone can help me sorting out this small task would be great. Given a matrix like the following: 100 3 3 3 3 3 ... 200 5 5 5 5 5 ... 400 1 1 1 1 1 ... 500 8 8 8 8 8 ... 900 0 0 0 0...

## convert data into matrix- awk

is it possible to count the number of keys based on state and cell and output it as a simple matrix. Ex: cell1-state1 has 2 keys cell3-state1 has 4 keys. Note: Insert 0 if no data available. input key states cell key1 state1 cell1 key1 state2 cell1 key1 ...

## Converting to matrix-like file using AWK

Hi, Needs for statistics, doing converting Here is a sample file Input : 1|A|17,94 1|B|22,59 1|C|56,93 2|A|63,71 2|C|23,92 5|B|19,49 5|C|67,58 expecting something like that Output : 1|A|17,94|B|22,59|C|56,93 2|A|63,71|B|0|C|23,92 5|A|0|B|19,49|C|67,58

## how to rearrange a matrix with awk

Hi, every one. I have two files ,one is in matrix like this, one is a list with the same data as the matrix. AB AE AC AD AA AF SA 3 4 5 6 4 6 SC 5 7 2 8 4 3 SD 4 6 5 3 8 3 SE 45 ...

## How order a data matrix using awk?

is it possible to order the following row clusters from ascending to descending. thanx in advance input 1 2 4 0 1 2 4 0 3 3 3 3 1 5 1 0 1 5 1 0 6 0 0 0 5 1 1 1...

## How to sum the matrix using awk?

input A1 B1 A2 B2 0 0 1 1 1 0 0 1 0 1 1 0 1 1 1 1 Output label A1 B1 A2 B2 A1 2 1 1 2 B1 1 2 2 1 A2 1 2 3 2 B2 2 1 2 3 Ex: The number of times that A1 and B1 row values are both 1 should be printed as output. The last row of A1 and B1 in the input match by having 1 in both...
```A2P(1)							 Perl Programmers Reference Guide						    A2P(1)

NAME
a2p - Awk to Perl translator

SYNOPSIS
a2p [options] [filename]

DESCRIPTION
A2p takes an awk script specified on the command line (or from standard input) and produces a comparable perl script on the standard out-
put.

OPTIONS

Options include:

-D<number>
sets debugging flags.

-F<character>
tells a2p that this awk script is always invoked with this -F switch.

-n<fieldlist>
specifies the names of the input fields if input does not have to be split into an array.  If you were translating an awk script that
processes the password file, you might say:

Any delimiter can be used to separate the field names.

-<number>
causes a2p to assume that input will always have that many fields.

-o   tells a2p to use old awk behavior.	The only current differences are:

*	 Old awk always has a line loop, even if there are no line actions, whereas new awk does not.

*	 In old awk, sprintf is extremely greedy about its arguments.  For example, given the statement

print sprintf(some_args), extra_args;

old awk considers extra_args to be arguments to "sprintf"; new awk considers them arguments to "print".

"Considerations"

A2p cannot do as good a job translating as a human would, but it usually does pretty well.  There are some areas where you may want to
examine the perl script produced and tweak it some.  Here are some of them, in no particular order.

There is an awk idiom of putting int() around a string expression to force numeric interpretation, even though the argument is always inte-
ger anyway.  This is generally unneeded in perl, but a2p can't tell if the argument is always going to be integer, so it leaves it in.  You
may wish to remove it.

Perl differentiates numeric comparison from string comparison.  Awk has one operator for both that decides at run time which comparison to
do.  A2p does not try to do a complete job of awk emulation at this point.  Instead it guesses which one you want.  It's almost always
right, but it can be spoofed.  All such guesses are marked with the comment ""#???"".  You should go through and check them.  You might
want to run at least once with the -w switch to perl, which will warn you if you use == where you should have used eq.

Perl does not attempt to emulate the behavior of awk in which nonexistent array elements spring into existence simply by being referenced.
If somehow you are relying on this mechanism to create null entries for a subsequent for...in, they won't be there in perl.

If a2p makes a split line that assigns to a list of variables that looks like (Fld1, Fld2, Fld3...) you may want to rerun a2p using the -n
option mentioned above.	This will let you name the fields throughout the script.  If it splits to an array instead, the script is probably
referring to the number of fields somewhere.

The exit statement in awk doesn't necessarily exit; it goes to the END block if there is one.  Awk scripts that do contortions within the
END block to bypass the block under such circumstances can be simplified by removing the conditional in the END block and just exiting
directly from the perl script.

Perl has two kinds of array, numerically-indexed and associative.  Perl associative arrays are called "hashes".	Awk arrays are usually
translated to hashes, but if you happen to know that the index is always going to be numeric you could change the {...} to [...].  Itera-
tion over a hash is done using the keys() function, but iteration over an array is NOT.	You might need to modify any loop that iterates
over such an array.

Awk starts by assuming OFMT has the value %.6g.	Perl starts by assuming its equivalent, \$#, to have the value %.20g.  You'll want to set
\$# explicitly if you use the default value of OFMT.

Near the top of the line loop will be the split operation that is implicit in the awk script.  There are times when you can move this down
past some conditionals that test the entire record so that the split is not done as often.

For aesthetic reasons you may wish to change the array base \$[ from 1 back to perl's default of 0, but remember to change all array sub-
scripts AND all substr() and index() operations to match.

Cute comments that say "# Here is a workaround because awk is dumb" are passed through unmodified.

Awk scripts are often embedded in a shell script that pipes stuff into and out of awk.  Often the shell script wrapper can be incorporated
into the perl script, since perl can start up pipes into and out of itself, and can do other things that awk can't do by itself.

Scripts that refer to the special variables RSTART and RLENGTH can often be simplified by referring to the variables \$`, \$& and \$', as long
as they are within the scope of the pattern match that sets them.

The produced perl script may have subroutines defined to deal with awk's semantics regarding getline and print.	Since a2p usually picks
correctness over efficiency.  it is almost always possible to rewrite such code to be more efficient by discarding the semantic sugar.

For efficiency, you may wish to remove the keyword from any return statement that is the last statement executed in a subroutine.  A2p
catches the most common case, but doesn't analyze embedded blocks for subtler cases.

ARGV[0] translates to \$ARGV0, but ARGV[n] translates to \$ARGV[\$n].  A loop that tries to iterate over ARGV[0] won't find it.

ENVIRONMENT
A2p uses no environment variables.

AUTHOR
Larry Wall <larry@wall.org>

FILES
perl   The perl compiler/interpreter

s2p    sed to perl translator

DIAGNOSTICS
BUGS
It would be possible to emulate awk's behavior in selecting string versus numeric operations at run time by inspection of the operands, but
it would be gross and inefficient.  Besides, a2p almost always guesses right.

Storage for the awk syntax tree is currently static, and can run out.

perl v5.8.9							    2005-03-10								    A2P(1)```

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