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awk - Read fixed format

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# 1  
Old 05-15-2013
awk - Read fixed format
Hi,
I have several fixed format ascii files which I would like to reformat through Awk. The fixed format produces intermittent whitespace (Nastran input file).

Code:
 
$ Grid points
$------1-------2-------3-------4-------5-------6-------7-------8-------9-------0
GRID* 1 0-2.79677946159+2-1.85355339059+2
* 1.000000000000+1 0
GRID* 2 0-2.79677946159+2-1.75355339059+2
* 1.000000000000+1 0
GRID* 3 0-2.79677946159+2-1.65355339059+2
* 1.000000000000+1 0
GRID* 4 0-2.79677946159+2-1.55355339059+2
* 1.000000000000+1 0
 
GRID* 16 0-2.79677946159+2-3.53553390593+1
* 1.000000000000+1 0
GRID* 17 0-2.44322607100+2 0.0
* 1.000000000000+1 0
GRID* 18 0-2.51393674912+2 -7.071067811865
* 1.000000000000+1 0
GRID* 44 0-1.49585269653+1-1.4673061224-13
* 1.000000000000+1 0
GRID* 45 0 -4.986175655110-1.5311020408-13
* 1.000000000000+1 0
GRID* 46 0 4.9861756551108-1.5948979591-13
* 1.000000000000+1 0
GRID* 47 01.495852696533+1-1.6586938775-13
* 1.000000000000+1 0

The Awk script that I have mashed together so far (adding an 'E' to make standard scientific format, then removing the unwanted 'E' at the beginning of the fields that have a minus sign, operating on different cases to cope with the intermittent whitespace, not clever!) is as follows :

Code:
 
awk '/GRID/ {
a = NF;
printf "%s\t",a;
if ($3 != 0 && NF == 3){
$3 = substr($3,2);
$4 = substr($3,1,16);
$5 = substr($3,17,32);
gsub(/+/,"E+");
gsub(/-/,"E-");
/^[E]/; $4 = substr($4,2); $5 = substr($5,2)
}
if ($3 == 0 && NF == 4){
b = length($4);
printf "%s\t",b;
#$4 = substr($4,1,b-1-16);
$4 = substr($4,1,15);
#$5 = substr($4,b-1);
$5 = substr($4,16);
#$4 = 444;
#$5 = 555;
gsub(/+/,"E+");
gsub(/-/,"E-");
/^[E]/; $4 = substr($4,2); $5 = substr($5,2)
}
printf "%-4i%20e%20e\n",$2,$4,$5}' data.txt > revdata.txt

The data that I require is $2 following the '/GRID/, the next two numbers in scientific format and $2 on the next line (after the *). I would prefer to keep the whole process within Awk for my slant on being portable.
Does anyone have a smarter strategy to trap this number format?

Regards, Tim
Last edited by Scrutinizer; 05-15-2013 at 01:09 PM.. Reason: fixed code tags - use 'code' istead of 'icode' - Also changed quote tags to code tags
# 2  
Old 05-15-2013
Can you post a sample of the desired output...
# 3  
Old 05-15-2013
Hi Shamrock,
Thank you for your reply.

This data represents X Y Z coordinates.

The desired output format is:
Code:
 
1 -2.796779e+02 -1.853553e+02 1.000000e+01
2 -2.796779e+02 -1.753553e+02 1.000000e+01
3 -2.796779e+02 -1.653553e+02 1.000000e+01
4 -2.796779e+02 -1.553553e+02 1.000000e+01
16 -2.796779e+02 -3.535534e+01 1.000000e+01
17 -2.4432260+02 0.000000e+00 1.000000e+01
18 -2.5139367+02 -7.071067e+00 1.000000e+01
44 -1.495853e+01 -1.467306e-13 1.000000e+01
45 -4.986176e+00 5.500000e+01 1.000000e+01
46 9.861757e-01 5.500000e+01 1.000000e+01
47 4.958527e+00 -1.658694e-13 1.000000e+01

Regards, Tim
Last edited by Scrutinizer; 05-15-2013 at 01:09 PM.. Reason: quote tags to code tags
# 4  
Old 05-15-2013
And there is no whitespace between the the 3rd and 4th fields correct...
Code:
GRID* 47 01.495852696533+1-1.6586938775-13

# 5  
Old 05-15-2013
The format of the input file is data sets that occupy two lines each.
In line 1 of 1: field 1 is 'GRID*', field 2 is the unique label, field 3 is zero, field 4 is 'X', field 5 is 'Y'.
In line 2 of 2: field 1 is the continuation character '*', field 2 is 'Z', field 3 is zero.

My difficulty is that the fixed fields 4 and 5 on line 1 of 1 are often full (no whitespace) but can be less than full as in example input below, where there can is whitespace between fields 3 and 4 (GRID* 45) and between fields 4 and 5 (GRID* 18):
Quote:
GRID* 18 0-2.51393674912+2 -7.071067811865
* 1.000000000000+1 0
GRID* 44 0-1.49585269653+1-1.4673061224-13
* 1.000000000000+1 0
GRID* 45 0 -4.986175655110-1.5311020408-13
* 1.000000000000+1 0
Tim
# 6  
Old 05-15-2013
Try this sed and awk pipeline...
Code:
sed -e 's/\([0-9]\)\([0-9]\)\([.]\)\([0-9]\)/\1 \2\3\4/g' -e 's/\([0-9]\)\([+-]\)\([0-9]\)\([.]\)/\1 \2\3\4/g' data.txt | \
awk '{s = $2 OFS $4 OFS $5; getline; if ($0 ~ "^[*]") s = s OFS $2; print s}' > revdata.txt

# 7  
Old 05-15-2013
Shamrock,
Your concise code does the job proficiently; I greatly appreciate your help.
Regards, Tim
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