最佳实践:在 bash 脚本中打印数组 [英] Best Practice : Print an array in a bash script

问题描述

我在脚本上运行了 shellcheck 并在一个非常简单的方面遇到了错误 -

I ran shellcheck on my script and ran into an error on a very simple aspect -

echo "删除的字段列表:${deleted[@]}"
^-----------^ SC2145:参数混合字符串和数组.使用 * 或单独的参数.

echo "List of fields deleted: ${deleted[@]}"
^-----------^ SC2145: Argument mixes string and array. Use * or separate argument.

我正在尝试做如下类似的行为-

I am trying to do similar behavior as below-

declare -a  deleted
deleted = ("some.id.1" "some.id.22" "some.id.333")
echo "List of fields deleted: ${deleted[@]}"

打印数组中的元素哪个更好?

Which is a better practice to print the elements in the array?

echo "List of fields deleted: ${deleted[@]}"

或

echo "List of fields deleted: "
 for deletedField in "${deleted[@]}"; do echo "${deletedField}"; done

推荐答案

在较长的字符串中包含一个 @ 索引数组可能会产生一些奇怪的结果:

Including a @-indexed array inside a longer string can make for some weird results:

$ arr=(a b c)
$ printf '%s\n' "Hi there ${arr[@]}"
Hi there a
b
c

发生这种情况是因为 ${arr[@]} 的引用扩展是一系列 单独的 单词，printf 将使用一个一次.第一个单词 a 以 Hi there 结尾(就像数组后面的任何内容都将附加到 c 一样).

This happens because the quoted expansion of ${arr[@]} is a series of separate words, which printf will use one at a time. The first word a ends up with Hi there prepended to it (just as anything following the array would be appended to c).

当数组扩展是较大字符串的一部分时，您几乎肯定希望扩展是单个单词.

When the array expansion is part of a larger string, you almost certainly want the expansion to be a single word instead.

$ printf '%s\n' "Hi there ${arr[*]}"
Hi there a b c

使用 echo 时，它几乎不重要，因为您可能不关心 echo 是接收一个还是多个参数.

With echo, it barely matters, as you probably don't care whether echo is receiving one or multiple arguments.

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