How can I awk, grep, sed, etc. the real and Im parts of a complex number?!?

[satyavan]

I have a file of complex numbers written in their real+imaginary parts but without spaces and of different length and with or without exponentials, such as:

0.4672547e-7+.95475538e-3i
.4574785e-1+0.274636i
1.58365834-.5982347e-2i
......

I would like to separate the above into real an imaginary parts as follows:

0.4672547e-7
.95475538e-3
.4574785e-1
0.274636
1.58365834
-.5982347e-2

I tried out built-in functions for string manipulation like awk, sed, grep, etc. but could not find a way to do that. Can anyone help?

Thanks in advance.

[smolloy]

Thinking pretty quickly here, but I think awk can do it. If there are spaces between the real part and the plus/minus and the imaginary part, then awk should be able to pull out each number individually.

awk -F " " '{print $1 "\n" $3}' yourfile.txt

PS:: I really hope I'm not helping you cheat with your homework here....

[satyavan]

hmmm... no this separates only the lines, but the real and imaginary parts remain "glued" together.

[smolloy]

The line I gave you will only separate them correctly if there are spaces in the lines (as I said).

The following will work fine.

x + yi

Whereas the following won't,

x+yi

Maybe you could use sed to add those spaces? Search for instances of "+" or "-" that don't have an "e" before them, and replace them with " + " or " - ". Then my original awk line will work.

[eggi]

Hey There,

This will work perfectly for your sample script, but is very specific. If it doesn't do the trick, throw out some more random data

# sed -e 's/-\./\n-/' -e 's/\+/\n/' -e 's/i$//' YOURFILE
0.4672547e-7
.95475538e-3
.4574785e-1
0.274636
1.58365834
-5982347e-2


Best wishes,

Mike

[drl]

Hi.

This recognizer seems fairly robust:

#!/usr/bin/perl

# @(#) p2       Demonstrate pattern matching floating point.
#
# Adapted from 'The AWK Programming Language", page 40.

use warnings;
use strict;

my($debug);
$debug = 1;
$debug = 0;

my ($sign,$decimal,$fraction,$exponent,$number);
$sign = "[+-]?";
$decimal = "[0-9]+[.]?[0-9]*";
$fraction = "[.][0-9]+";
$exponent = "([eE] $sign [0-9]+)?";
# $number = sign "(" decimal "|" fraction ")" exponent;
$number = "$sign ( $decimal | $fraction ) $exponent";
print " numpat = $number\n" if $debug;

my($lines) = 0;

while ( <> ) {
        chomp;
        $lines++;
        print "$1\n" while m{($number)}gxms;
}

print STDERR " ( Lines read: $lines )\n";

exit(0);

Producing (from your data on file "data1"):

% ./p2 data1
0.4672547e-7
+.95475538e-3
.4574785e-1
+0.274636
1.58365834
-.5982347e-2
 ( Lines read: 3 )

cheers, drl