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

问题描述

可以在bash中使用两个数组的差异。

如果你能建议我这样做，那真是太棒了。

代码：

  Array1 =（key1key2key3key4key5key6 key7key8key9key10）
 Array2 =（key1key2key3key4key5key6）
 
 Array3 = diff （array1，array2）
 
 Array3理想地应该是：
 Array3 =（key7key8key9key10）
  / pre> 
 
 
感谢您的帮助。
解决方案
  Array1  -  Array2 ，
 
 $ Array3 = for i in$ {Array1 [@]}; do 
>     skip = 
>     forin $ {Array2 [@]}; do 
>          [[$ i == $ j]] && {skip = 1;打破; } 
>     done 
>     [[-n $ skip]] || Array3 + =（$ i）
> done 
 $ declare -p Array3 
 
可以使用关联数组改进运行时，但我个人不会打扰。 
 
 
 
 
 
 
对于像Dennis的对称差异answer，  comm  工作，只要我们按下输入和输出一点（因为他们工作在基于行的文件，而不是shell变量）。
 
 
 
 shell使用换行符将数组连接成单个字符串，并且当从 comm 读取回到数组时舍弃制表符。
 
 $ oldIFS = $ IFS IFS = $'\\\
\t'
 $ Array3 =（$（comm -3<（echo$ {Array1 [ *]}）<（echo$ {Array2 [*]}）））
 comm：文件1不按排序顺序
 $ IFS = $ oldIFS 
 $ declare  - p Array3 
 declare -a Array3 ='（[0] =key7[1] =key8[2] =key9[3] =key10）'
 
它抱怨，因为通过字典排序， key1< ...< key9> key10 。但是由于两个输入数组的排序是相似的，忽略这个警告是很好的。您可以使用  -  nocheck-order 摆脱警告，或者添加 |如果您不能保证输入数组的顺序和唯一性，请在<（...）过程替换中排序-u  
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" )
Appreciate your help.
解决方案
If you strictly want Array1 - Array2, then
$ 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
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.



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).

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")'
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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