CODEWITHSUNDEEP
bashlistshellfor-loop
X99
X99

Reputation: 915

bash: iterate over array of integers and avoid a value

I'd like to do this in a shell script:

valueToAvoid = [1, 5, 30]
for i in alist
  if i not in valuesToAvoid then
    doSomething
  endif
endfor

Can someone help?

Upvotes: 0

Views: 1985

Answers (1)

rici
rici

Reputation: 241861

If you have bash4, you can put your forbidden values in an associative array:

declare -A avoid
for val in 1 5 30; do avoid[$val]=1; done

for val in {0..99}; do
  if ! [[ ${avoid[$val]} ]]; then
    # Whatever
  fi
done

Another alternative is to scan the values to be avoided using, for example, grep. This is probably less efficient but it doesn't require bash 4 features:

avoid=(this that "the other")
# Avoided values, one per line. I could have done this with a here-doc,
# but sometimes it's useful to convert an array to a sequence of lines
avoid_lines=$(printf %s\\n "${avoid[@]}")

for val in one "the other" two; do
  if ! grep -qFx -e"$val" <<<"$avoid_lines"; then
    # Whatever
  fi
done

Upvotes: 2

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