linux shell数组操作

  1. 定义数组
    [chengmo@centos5 ~]$ a=(1 2 3 4 5)
    [chengmo@centos5 ~]$ echo $a
    1
    [chengmo@centos5 ~]$ a=([1]=aaa [2]=bbb [c]=ccc)
    [chengmo@centos5 ~]$ echo ${a[c]}
    ccc
    [chengmo@centos5 ~]$ b[1]=100
    [chengmo@centos5 ~]$ echo ${b[1]}
    100
    [chengmo@centos5 ~]$ a="one two three"  # echo ${array[0|@|*]},把array变量当作数组来处理,但数组元素只有字符串本身

  2. 读取与赋值
    得到长度(用${#数组名[@或*]} 可以得到数组长度):
    [chengmo@centos5 ~]$ echo ${#a[@]}
    5读取(用${数组名[下标]} 下标是从0开始 下标是:*或者@ 得到整个数组内容):
    [chengmo@centos5 ~]$ echo ${a[2]}
    3
    [chengmo@centos5 ~]$ echo ${a[*]}
    1 2 3 4 5赋值(直接通过 数组名[下标] 就可以对其进行引用赋值,如果下标不存在,自动添加新一个数组元素):
    [chengmo@centos5 ~]$ a[1]=100
    [chengmo@centos5 ~]$ echo ${a[*]}
    1 100 3 4 5
    [chengmo@centos5 ~]$ a[5]=100
    [chengmo@centos5 ~]$ echo ${a[*]}
    1 100 3 4 5 100删除(直接通过:unset 数组[下标] 可以清除相应的元素,不带下标,清除整个数据):
    [chengmo@centos5 ~]$ a=(1 2 3 4 5)
    [chengmo@centos5 ~]$ unset a
    [chengmo@centos5 ~]$ echo ${a[*]}

    [chengmo@centos5 ~]$ a=(1 2 3 4 5)
    [chengmo@centos5 ~]$ unset a[1]
    [chengmo@centos5 ~]$ echo ${a[*]}
    1 3 4 5
    [chengmo@centos5 ~]$ echo ${#a[*]}
    4

  3. 特殊使用
    分片(直接通过 ${数组名[@或*]:起始位置:长度} 切片原先数组,返回是字符串,中间用“空格”分开,因此如果加上”()”,将得到切片数组,上面例子:c 就是一个新数据):
    [chengmo@centos5 ~]$ a=(1 2 3 4 5)
    [chengmo@centos5 ~]$ echo ${a[@]:0:3}
    1 2 3
    [chengmo@centos5 ~]$ echo ${a[@]:1:4}
    2 3 4 5
    [chengmo@centos5 ~]$ c=(${a[@]:1:4})
    [chengmo@centos5 ~]$ echo ${#c[@]}
    4
    [chengmo@centos5 ~]$ echo ${c[*]}
    2 3 4 5替换(调用方法是:${数组名[@或*]/查找字符/替换字符} 该操作不会改变原先数组内容,如果需要修改,可以看上面例子,重新定义数据):
    [chengmo@centos5 ~]$ a=(1 2 3 4 5)
    [chengmo@centos5 ~]$ echo ${a[@]/3/100}
    1 2 100 4 5
    [chengmo@centos5 ~]$ echo ${a[@]}
    1 2 3 4 5
    [chengmo@centos5 ~]$ a=(${a[@]/3/100})
    [chengmo@centos5 ~]$ echo ${a[@]}
    1 2 100 4 5
    [chengmo@centos5 ~]$ array=( [0]=one [1]=two [2]=three [3]=four )
    [chengmo@centos5 ~]$ echo ${array[@] /o/m}   #第一个匹配的会被删除
    mne twm three fmur
    [chengmo@centos5 ~]$ echo ${array[@] //e/f}   #所有匹配的会被删除
    onf two thrff four
    [chengmo@centos5 ~]$ echo ${array[@] //o/}   #没有指定替换子串,则删除匹配到的子符
    ne tw three fur
    [chengmo@centos5 ~]$ echo ${array[@] /#o/k}   #替换字符串前端子串
    kne two three four
    [chengmo@centos5 ~]$ echo ${array[@] /%o/k}   #替换字符串后端子串
    one twk three four

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