关联bash中数组中一个键的多个值 [英] associate multiple values for one key in array in bash

问题描述

我有一个文本文件，如下所示:

I have a text file that looks like:

1 aaaa
2 bbbb
3 cccc
4 dddd
2 eeee
2 ffff
4 gggg

我想将它们映射到某种关联数组中，以便访问例如与键2关联的所有值和与键4关联的所有值，等等:

I would like to map these into some sort of associative array so that I can access, for example, all the values associated with the key 2 and all the values associated with the key 4, etc.:

1->aaaa
2->bbbb,eeee,ffff
3->cccc
4->dddd,gggg

我无法弄清楚如何使用"declare -A MYMAP"来做到这一点.有一些简单的方法可以做到这一点吗?

I haven't been able to figure out how to do this with 'declare -A MYMAP'. Is there some easy way to do this?

--------更新--------

--------update--------

我的键/值对实际上看起来像这样:

my key/value pairs look like this actually:

bb126.B1 bb126.1.ms.01
bb126.B2 bb126.1.ms.02
bb126.B3 bb126.1.ms.03
bb126.B4 bb126.1.ms.04

推荐答案

这是使用关联数组:

# store
declare -A array # this is the only update
while read key value; do
    array[$key]="${array[$key]}${array[$key]:+,}$value"
done < file
# print
for key in "${!array[@]}"; do echo "$key->${array[$key]}"; done

---

说明

array[$key]="${array[$key]}${array[$key]:+,}$value"

保存array[$key]中以,分隔的每个$value:

• ${array[$key]}保存以前的值(如果有).
• ${array[$key]:+,}如果有以前的值，则会添加,.
• $value添加新的读取值.

• ${array[$key]} save previous value(s) (if any).
• ${array[$key]:+,} adds a , if there's a previous value.
• $value adds the new read value.

for key in "${!array[@]}"; do echo "$key->${array[$key]}"; done

打印与每个$key相关的值.

来自 man bash :

$ {parameter:+ word}
如果参数为null或未设置，则不替换任何内容，否则替换word的扩展名.

${parameter:+word}
If parameter is null or unset, nothing is substituted, otherwise the expansion of word is substituted.

$ {！name [@]}
$ {！name [*]}
如果name是数组变量，则扩展到name中分配的数组索引(键)列表.如果name不是数组，则在name设置为0时扩展为0，否则为null.如果使用"@"，并且扩展名出现在双引号中，则每个键都会扩展为一个单独的单词.

${!name[@]}
${!name[*]}
If name is an array variable, expands to the list of array indices (keys) assigned in name. If name is not an array, expands to 0 if name is set and null otherwise. When ‘@’ is used and the expansion appears within double quotes, each key expands to a separate word.

---

示例

$ cat file
1 aaaa
2 bbbb
3 cccc
4 dddd
2 eeee
2 ffff
4 gggg

$ ./script.sh 
1->aaaa
2->bbbb,eeee,ffff
3->cccc
4->dddd,gggg

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