Finding indices in an array nearest to a set of values

Shell Programming and Scripting
1

I have an two arrays. One array BINDIST consists of fences. I have another array XOFFS.

Eg

BINDIST = 0 10 20 30 40 50 60

XOFFS = 2 3 4 23 25 28 55 58

I want to find to find the indices of values in XOFFS that are closest to each BINDIST.

My idea is to do as follows

I create array XMIDS such that

XMIDS(I) = ( BINDIST(I) + BINDIST(I+1) ) / 2, for I = 1 to NBINDIST-1

Then I check values in XOFFS such that

I find all XOFFS between BINDIST(1) and XMID(1), and choose among these, the closest to BINDIST(1)
Save in VALS(1)

I find all XOFFS between XMIDS(I) and XMIDS(I+1) , and choose among these, the closest to BINDIST(I+1), for I = 1 to NBINDIST-2
Save in VALS(I+1)

I find all XOFFS between XMIDS(NBINDIST-1) and BINDIST(NBINDIST) , and choose among these, the closest to BINDIST(NBINDIST)
Save in VALS(NBINDIST)

If I don't find any XOFFS if the regions described, I return ZERO to the corresponding VALS.

Result should be

VALS = 2 0 23 28 0 55 58
2

what is the results surpposed to be?

3 
VALS = 2 0 23 28 0 55 58
4

try:

echo -e "${XOFFS[@]}\n${BINDIST[@]}" |\
awk  'NR==1{len=split($0,X);next}
{for(i=1;i<=NF;i++){
   t=x=0
   for(j=1;j<=len;j++){
      x=sqrt((X[j]-$i)*(X[j]-$i))
      if(j==1){t=x}else{t=t<x?t:x}
      a[x]=X[j]}
      printf  t<=5?a[t]" ":"0 "
      delete a}
   printf "\n"}'
2 0 23 28 0 55 58
5

Coded the following csh script and got the correct result

2 0 23 28 0 55 58

#!/bin/csh

set XOFFS = (2 3 4 23 25 28 55 58)
set BINDIST = (0 10 20 30 40 50 60)
echo $XOFFS
echo "${XOFFS}\n${BINDIST}" |        \
  awk  'NR == 1 { len = split($0, X); next }  \
    { for (i=1; i<=NF; i++) {           \
      t = x = 0                         \
      for (j=1; j<=len; j++) {          \
        x = sqrt((X[j]-$i)*(X[j]-$i))   \
        if(j==1) {t=x} else {t=t<x?t:x} \
        a[x] = X[j]                     \
      }                                 \
      printf t<=5?a[t]" ":"0 "          \
      delete a                          \
    }                                   \
      printf "\n"                       \
    }'

---------- Post updated at 08:35 PM ---------- Previous update was at 08:21 PM ----------

Got no idea how this code is working. Why do you use a[x] and what's the sqrt about. You did not calculate XMIDS

6

I don't know if this codes can be run in csh, I did it in bash.

#!/bin/bash
XOFFS=(2 3 4 23 25 28 55 58) # array 
BINDIST=(0 10 20 30 40 50 60) # array 
echo ${XOFFS[@]} echo -e "${XOFFS[@]}\n${BINDIST[@]}"|\
awk  'NR==1{len=split($0,X);next}
{for(i=1;i<=NF;i++){
   t=x=0
   for(j=1;j<=len;j++){
      x=sqrt((X[j]-$i)*(X[j]-$i))
      if(j==1){t=x}else{t=t<x?t:x}
      a[x]=X[j]}
      printf  t<=5?a[t]" ":"0 "
      delete a}
      printf "\n"}'
7

It works but trying to figure out the calculations. Values in both XOFFS and BINDIST will have both negative and positive values.
The values can be floating point, not just integers.

8 
awk  'NR==1{len=split($0,X);next}
 {for(i=1;i<=NF;i++){
    t=x=0
    for(j=1;j<=len;j++){ 
    x=sqrt((X[j]-$i)*(X[j]-$i)) # if the value of X[j]-$i could be negative or positive, this calculation make this value to be absolute value, since there is no abs function in awk, ps. sqrt is SQuare Roo
       if(j==1){t=x}else{t=t<x?t:x}
       a[x]=X[j]}
       printf  t<=5?a[t]" ":"0 " # if abs value of X[j]-$i (t) is less than or equal to 5, accept as the closet value, if not, set it as 0
         delete a}       printf "\n"}'