Merge two files depending on range using awk - awk

Question

I have a file (let's call it main.txt) where the 1st column contains some numbers (2, 4, 8, 15).
2 OtherData
4 OtherData
8 OtherData
15 OtherData
Also, I have other file mapping.txt. I want to compare each value from main.txt (2, 4, 8, 15) with first 2 columns of mapping file.
The 1st column is a minimum allowed value, the 2nd is a maximum.
1 4 1stType
5 9 2ndType
10 14 3rdType
15 99 4thType
100 1000 5thType
How can I get a result like this using awk?
2 OtherData 1stType # 1 <= 2 <= 4
4 OtherData 1stType # 1 <= 4 <= 4
8 OtherData 2ndType # 5 <= 8 <= 9
15 OtherData 4thType # 15 <= 15 <= 100

Answer 1

Could you please try following, written and tested with shown samples only in GNU awk.
awk '
FNR==NR{
++count
start[count]=$1
end[count]=$2
value[count]=$NF
next
}
{
for(i=1;i<=count;i++){
if($1>=start[i] && $1<=end[i]){
print $0,value[i]
}
}
}
' Input_file2 Input_file1 | column -t
Output will be as follows.
2 OtherData 1stType
4 OtherData 1stType
8 OtherData 2ndType
15 OtherData 4thType

Answer 2

A shorter awk solution that loops through range and store mapping in an array:
awk 'NR == FNR {
for (i=$1; i<=$2; i++)
map[i] = $3
next
}
$1 in map {
print $0, map[$1]
}' mapping.txt main.txt
2 OtherData 1stType
4 OtherData 1stType
8 OtherData 2ndType
15 OtherData 4thType
Alternative awk:
awk 'NR == FNR {
map[$1,$2] = $3
next
}
{
for (i in map) {
split(i, a, SUBSEP)
if ($1 >= a[1] && $1 <= a[2]) {
print $0, map[i]
next
}
}
}' mapping.txt main.txt