Ubuntu12.04 TLS 64bit, bash 4.2.25
一、定义
数组是一些数据的集合，分为两个类型
(1)普通数组，只能使用整数作为索引
(2)关联数组，可以使用字符串作为索引，bash 4.0开始支持，旧版版不支持
二、数组的一些操作
(1)数组的定义以及赋值
<普通数组>
【1】定义
数组名 = ()
【2】赋值
1. 数组名 = (elem1 elem2 elem3 ......)
每个元素由空格隔开
2. 数组名[0] = "test1"
数组名[1] = "test2"
......
<关联数组>
【1】定义
declare -A 数组名
【2】赋值
1. 数组名 = ([index1] = val1 [index2] = val2 .....)
2. 数组名[index1] = val1
数组名[index2] = val2
......
(2)求数组的长度
${#数组名[*]} 或 {#数组名[@]}
(3)获得数组制定索引的元素
${数组名[索引值]}
(4)获得数组的所有元素
${数组名[*]} 或 ${数组名[@]}
(5)数组元素的替换
${数组名[*]/查找字符/替换字符} 或 ${数组名[@]/查找字符/替换字符}
替换并没有改变原来的数组，要修改原来的数组，需要对数组重新赋值
(6)删除数组元素
unset 数组名 #删除整个数组 unset 数组名[索引值] #删除指定的元素
(7)数组的切片
${数组名[*]:起始位置:长度} 或 ${数组名[@]:起始位置:长度}
切片后返回的是由空格隔开的字符串，加上()后将得到切片后的子数组
三、例子
#!/bin/bash
#定义普通数组并进行赋值
comm_arr=(1 2 3 4 5)
comm_arr2=()
comm_arr2[0]=6
comm_arr2[1]=7
comm_arr2[2]=8
#获得普通数组的长度
echo "comm_arr1 len is ${#comm_arr[*]}"
echo "comm_arr2 len is ${#comm_arr2[@]}"
#获得普通数组的所有元素
echo "comm_arr1 all elem is : ${comm_arr[*]}"
echo "comm_arr2 all elem is ：${comm_arr2[@]}"
#通过索引获得元素
echo "comm_arr[4] = ${comm_arr[4]}"
echo "comm_arr[2] = ${comm_arr2[2]}"
echo "comm_arr[100] = ${comm_arr[100]}" #索引值不存在，但不出错，结果为空
#普通数组中元素的替换
echo "3 in comm_arr is replace 200 : ${comm_arr[*]/3/200}"
echo "comm_arr is ${comm_arr[*]}" #原数组没有被修改
comm_arr2=(${comm_arr2[@]/7/9}) #替换原数组
echo "7 in comm_arr2 is replace 9 and modify comm_arr2"
echo "comm_arr2 is ${comm_arr2[*]}"
#普通数组的切片
echo "splite comm_arr 1-3 is : ${comm_arr[*]:1:3}"
comm_arr_split=(${comm_arr[@]:2:3}) #获得从第三个位置子开始3个元素的子数组
echo "sub arr : len = ${#comm_arr_split[*]} , elems is : ${comm_arr_split[@]}"
#普通数组的删除
echo "del before, comm_arr is ${comm_arr[*]}"
echo "del a elem"
unset comm_arr[0] #删除某个元素
echo "del after, comm_arr is ${comm_arr[*]}"
echo "del all arr"
unset comm_arr #删除整个数组
echo "del after, comm_arr is ${comm_arr[*]}" #为空
#定义关联数组并赋值
declare -A link_arr
link_arr[‘apple‘]=‘10$‘
link_arr[orange]=‘100Y‘
declare -A link_arr2
link_arr2=([age]=20 [name]=zhangsan [sex]=m)
#获得关联数组的长度
echo "link arr len: ${#link_arr[*]}"
echo "link arr2 len: ${#link_arr2[@]}"
#通过索引获得元素
echo "link arr index=apple, elem is ${link_arr[‘apple‘]}"
echo "link arr2 index=name, elem is ${link_arr2[name]}"
echo "link arr index=name not exist, but no error, ${link_arr[name]}" #虽然没有这个索引，但不会错误，只是结果为空
#输出关联数组中所有元素
echo "apple is ${link_arr[*]}"
echo "link_arr2 is ${link_arr2[@]}"
#关联数组中的替换
echo "link arr2 zhangsan is replace lisi, ${link_arr2[*]/zhangsan/lisi}" #原数组没有修改
echo "link arr2 is ${link_arr2[*]}"
#link_arr2=(${link_arr2[*]/zhangsan/lisi}) #报错，关联数组必须使用下标
#echo "link arr2 is ${link_arr2[*]}"
#echo "link arr2 name=${link_arr2[name]}"
#关联数组的切片
echo "link arr2 age-name: ${link_arr2[*]:name:2}"
#关联数组的删除
echo "del before link arr2 is ${link_arr2[*]}"
unset link_arr2[age]
echo ""del after link arr2 is ${link_arr2[*]}
unset link_arr
echo "del all arr ${link_arr[*]}"
结果：
comm_arr1 len is 5
comm_arr2 len is 3
comm_arr1 all elem is : 1 2 3 4 5
comm_arr2 all elem is ：6 7 8
comm_arr[4] = 5
comm_arr[2] = 8
comm_arr[100] =
3 in comm_arr is replace 200 : 1 2 200 4 5
comm_arr is 1 2 3 4 5
7 in comm_arr2 is replace 9 and modify comm_arr2
comm_arr2 is 6 9 8
splite comm_arr 1-3 is : 2 3 4
sub arr : len = 3 , elems is : 3 4 5
del before, comm_arr is 1 2 3 4 5
del a elem
del after, comm_arr is 2 3 4 5
del all arr
del after, comm_arr is
link arr len: 2
link arr2 len: 3
link arr index=apple, elem is 10$
link arr2 index=name, elem is zhangsan
link arr index=name not exist, but no error,
apple is 100Y 10$
link_arr2 is zhangsan 20 m
link arr2 zhangsan is replace lisi, lisi 20 m
link arr2 is zhangsan 20 m
link arr2 age-name: zhangsan 20
del before link arr2 is zhangsan 20 m
del after link arr2 is zhangsan m
del all arr