Bash - 如何检查变量值是否在数组中

Question

I have an array that has 6 values, i then have three more arrays with anywhere between 4 and 1 value. i want to loop through array 1 and check if the value from array one appears in array2, array 3 and array 4. Currently i have the below but it only appears to check my value from array1 against the first value in arrays 2,3 and 4. i have omitted array 3 and 4 but they would have the same for loop as array2 and be inside the loop for array1.

array1=("value1" "value2" "value3" "value4" "value5" "value6")

for i in "${array1}"; do

array2= ("value1" "value3" "value4" "value5")

for f in "${array2}; do
if [[ ${i} == ${f} ]]; then

echo "${i} in array1 matches ${f} in array2"
else
echo "${i} in array1 does not match any value in array2"
fi
done
done

Answer 1

I think that the best thing to do is to make a function

in_array () {
  search=$1
  shift        # remove first argument from list of args $@
  for val; do  # equivalent to `for val in "$@"`
    if [[ $search = $val ]]; then
      return   # returns exit code of the successful [[ test ]], 0
    fi
  done
  return 1
}

This returns 0 if the value is found, else 1 , allowing you to use it like:

array1=("value1" "value2" "value3" "value4" "value5" "value6")
array2=("value1" "value3" "value4" "value5")

for i in "${array1[@]}"; do
  if in_array "$i" "${array2[@]}"; then
    echo "$i in array1 is in array2"
  fi
done

Note that to loop through all the values of an array, the correct expansion is "${array[@]}" (with double quotes and [@] ).

Answer 2

This is possible in a single loop:

#!/usr/bin/env bash

array1=("value1" "value2" "value3" "value4" "value5" "value6")
array2=("value1" "value3" "value4" "value5")

while read -r -d '' -n 8 count && IFS= read -r value; do
  if [ "$count" -gt 1 ]; then
    # value is seen more than once, so it is in both arrays
    echo "${value} in array1 matches ${value} in array2"
  else
    # value is only seen once
    if printf $'%s\n' "${array1[@]}" | grep --quiet "$value"; then
      # value is from array1
      echo "${value} in array1 does not match any value in array2"
    fi
  fi
done< <(
  # Combine both arrays
  # Sort and count number of times each value appears
  # then feed the while loop
  printf $'%s\n' "${array1[@]}" "${array2[@]}" | sort | uniq --count
)