Tutorial

数组比较 Shell可以处理数组 数组是包含多个值的变量。任何变量都可以用作数组。数组的大小没有最大限制,也没有要求成员变量被连续索引或连续分配。 数组从零开始:第一个元素的编号为0。

basic construct

# array=(value1 value2 ... valueN)
array=(23 45 34 1 2 3)
#To refer to a particular value (e.g. : to refer 3rd value)
echo ${array[2]}  

#To refer to all the array values
echo ${array[@]}

#To evaluate the number of elements in an array
echo ${#array[@]}

Exercise

在本练习中,您将需要比较三个数组列表并编写所有三个数组的公共元素:

a=(3 5 8 10 6),b=(6 5 4 12),c=(14 7 5 7) 结果是共同点5。

Tutorial Code

#!/bin/bash # enter your array comparison code here

Expected Output

5

Solution

#!/bin/bash
# enter your array comparison code here
# initialize arrays a b c
a=(3 5 8 10 6) 
b=(6 5 4 12) 
c=(14 7 5 7)
#comparison of first two arrays a and b
for x in "${a[@]}"; do 
  in=false 
  for y in "${b[@]}"; do 
    if [ $x = $y ];then 
      # assigning the matching results to new array z
      z[${#z[@]}]=$x
    fi
  done 
done
#comparison of third array c with new array z
for i in "${c[@]}"; do 
  in=false
  for k in "${z[@]}"; do
    if [ $i = $k ];then
      # assigning the matching results to new array j
      j[${#j[@]}]=$i
    fi
  done 
done 
# print content of array j
echo ${j[@]}