arrays and getline

[rhnaeco]

i know this is easy and i should use arrays- however despite reading about them i still don't quite understand:

i have two files one containing:
1 Tidal Prism = 1.20397e+08 m2

the other:
1 profile area = 12309.8 m2
2 profile length = 1.06403 km

all i want to do is create a file like this which will be added to later:

1.20397e+0 12309.8


i have tried:
awk '
BEGIN {
while (getline < "tp1.txt")
{prism[$5]=1}
}
{
if ($3 == "area")
print prism[$5], $5
}' tp2.txt
but just get
1.20397e+08

i have also tried:

awk '{
if ($1 == "1")
print $5
}' tp1.txt tp2.txt

which works but obviously gives the answer in a column, rather than a line

as i said- i know the array is the problem but how do i know what x and y equals in name[x]=y, using my files as an example- i have seen y=1, y=$3, x=$1,$3 -help!!!!

thanks

rhnaeco

 

[rhnaeco]

ignore this message - having found

http://www-128.ibm.com/developerworks/library/l-awk2.html

i understand arrays much better and have been able to solve my problem- prism[1]=$5 - so close to my first attempt!

 

[Annihilannic]

Modifying your first attempt, which looked pretty good:

awk '
BEGIN {
   while (getline < "tp1.txt") { prism[$1]=$5 } 
}
   
$3 == "area" {
   print prism[$1], $5
}' tp2.txt

Basically you should be indexing the prism array using the identifier that uniquely identifies each item of data. In this case it appears to be $1, which is the line number?


Annihilannic.

 

[rhnaeco]

as i said-so close!! thanks for your reply- i think i understand arrays for awk a little better- the two $ confused me a lot! it's a pity that a lot of awk webpages seem to be the same text, so if the example is not clear, google is not always a help.

thanks again

 

[vgersh99]

I hate getline-s

awk '
FNR==NR { prism[$1]=$5; next }
  
$3 == "area" && $1 in prism {
   print prism[$1], $5
}' tp1.txt tp2.txt

vlad
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