比较/ bash中两个数组的区别 [英] Compare/Difference of two arrays in bash

问题描述

是否有可能采取在bash两个数组的差别。结果
将是非常巨大的，如果你可以建议我做它的方式。

Is it possible to take the difference of two arrays in bash.
Would be really great if you could suggest me the way to do it.

code：

Array1=( "key1" "key2" "key3" "key4" "key5" "key6" "key7" "key8" "key9" "key10" )
Array2=( "key1" "key2" "key3" "key4" "key5" "key6" ) 

Array3 =diff(Array1, Array2)

Array3 ideally should be :
Array3=( "key7" "key8" "key9" "key10" )

鸭preciate你的帮助。

Appreciate your help.

推荐答案

如果你想严格数组1 - ARRAY2 ，然后

$ Array3=()
$ for i in "${Array1[@]}"; do
>     skip=
>     for j in "${Array2[@]}"; do
>         [[ $i == $j ]] && { skip=1; break; }
>     done
>     [[ -n $skip ]] || Array3+=("$i")
> done
$ declare -p Array3

运行时可能与关联数组得到改善，但我个人不会理会。如果你正在操作要做到这事足够的数据，外壳是错误的工具。

Runtime might be improved with associative arrays, but I personally wouldn't bother. If you're manipulating enough data for that to matter, shell is the wrong tool.

对于喜欢丹尼斯的回答对称的差异，现有的工具，如 通讯 工作，只要我们的按摩输入和输出位（因为他们对基于行的文件工作，而不是shell变量）。

For a symmetric difference like Dennis's answer, existing tools like comm work, as long as we massage the input and output a bit (since they work on line-based files, not shell variables).

在这里，我们告诉shell使用换行符到阵列连接成一个字符串，并读取从通讯线路时回一个数组舍弃标签页。

Here, we tell the shell to use newlines to join the array into a single string, and discard tabs when reading lines from comm back into an array.

$ oldIFS=$IFS IFS=$'\n\t'
$ Array3=($(comm -3 <(echo "${Array1[*]}") <(echo "${Array2[*]}")))
comm: file 1 is not in sorted order
$ IFS=$oldIFS
$ declare -p Array3
declare -a Array3='([0]="key7" [1]="key8" [2]="key9" [3]="key10")'

据抱怨，因为通过lexographical排序，键1＆LT; ...＆LT; key9＆GT; key10 。但由于两个输入数组排序相似，它也可以忽略该警告。您可以使用 - NOCHECK订单来摆脱警告，或添加 |排序-u 的＆LT内部;（...）进程替换如果你不能保证秩序和放大器;输入数组的唯一性。

It complains because, by lexographical sorting, key1 < … < key9 > key10. But since both input arrays are sorted similarly, it's fine to ignore that warning. You can use --nocheck-order to get rid of the warning, or add a | sort -u inside the <(…) process substitution if you can't guarantee order&uniqueness of the input arrays.

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