将 JSON 数组转换为 Bash

我会jq逐行输出结果。然后使用 bashmapfile命令将行读入数组

mapfile -t correct < <(jq -r '.results[] | .correct_answer' <<<"$quiz")
declare -p correct

declare -a correct=([0]="Amazon" [1]="60 lbs" [2]="True")

对于不正确的答案，由于 bash 没有多维数组，我可以jq将不正确答案的数组输出为 CSV：

mapfile -t incorrect < <(jq -r '.results[] | .incorrect_answers | @csv' <<<"$quiz")
declare -p incorrect

declare -a incorrect=([0]="\"Netflix\",\"BBC\",\"CCTV\"" [1]="\"30 lbs\",\"50 lbs\",\"70 lbs\"" [2]="\"False\"")

然后：

$ echo "q $i: ans=${correct[i]}; wrong=${incorrect[i]}"
q 1: ans=60 lbs; wrong="30 lbs","50 lbs","70 lbs"

文档：

• 进程替换
• 这里字符串

假设您正在与用户交互：

i=0
read -p "Answer to question $i: " answer

if [[ $answer == "${correct[i]}" ]]; then
    echo Correct
elif [[ ${incorrect[i]} == *"\"$answer\""* ]]; then
    echo Incorrect
else
    echo Invalid answer
fi

请记住，内部运算符[[...]]不是字符串相等运算符，它是模式匹配运算符。==

• 第一个测试是简单的字符串比较
• 第二个测试查看包含不正确答案的 CVS 字符串是否包含双引号中的答案

扩展@ RomanPerekhrest的答案（现在就去投票吧）：

mapfile -t answers < <(jq -r '.results[] | [.correct_answer] + .incorrect_answers | @sh' <<<"$quiz")
declare -p answers

declare -a answers=([0]="'Amazon' 'Netflix' 'BBC' 'CCTV'" [1]="'60 lbs' '30 lbs' '50 lbs' '70 lbs'" [2]="'True' 'False'")

然后，你可以使用这样的东西

for i in "${!answers[@]}"; do
    declare -a "this_answers=( ${answers[i]} )"
    echo $i
    printf " > %s\n" "${this_answers[@]}"
done

0
 > Amazon
 > Netflix
 > BBC
 > CCTV
1
 > 60 lbs
 > 30 lbs
 > 50 lbs
 > 70 lbs
2
 > True
 > False

根据既定目标“我希望 bash 数组包含correct_answer并且incorrect_answers”您希望获得一个组合值数组。
无需运行 2 个不同jq的命令，整个组合序列可以由单个jq表达式组成：

对于单字数组项：

$ declare -a answers=($(jq -r '[.results[0].correct_answer] + .results[0].incorrect_answers | @sh' <<<"$quiz"))

@sh：

输入经过转义，适合在 POSIX shell 的命令行中使用。如果输入是数组，则输出将是一系列以空格分隔的字符串。

结果：

$ echo "${answers[2]}"
'BBC'
$ echo "${answers[0]}"
'Amazon'
$ echo "${answers[1]}"
'Netflix'
$ echo "${answers[@]}"
'Amazon' 'Netflix' 'BBC' 'CCTV'

要处理带有空格的项目（如 中的那些.results[1]），请使用以下方法readarray和@json选项：

$ readarray -t answers < <(jq -r '[.results[1].correct_answer] + .results[1].incorrect_answers | .[] |@json' <<<"$quiz")

结果：

$ echo "${answers[1]}"
"30 lbs"
$ echo "${answers[0]}"
"60 lbs"
$ echo "${answers[@]}"
"60 lbs" "30 lbs" "50 lbs" "70 lbs"
$ echo "${answers[2]}"
"50 lbs"

因为这个问题在我的脑海中提出，一个运行游戏的小脚本：

#!/usr/bin/env bash

main() {
    local -a questions
    mapfile -t questions < <(
        get_quiz |
        jq -r '.results[] | [.question] + [.correct_answer] + .incorrect_answers | @sh'
    )

    for i in "${!questions[@]}"; do
        local -a q="( ${questions[i]} )"
        question $((i+1)) "${q[@]}"
    done
}

question() {
    local num=$1 question=$2 correct=$3
    local -a answers=("${@:3}")

    # shuffle the answers
    mapfile -t answers < <(printf "%s\n" "${answers[@]}" | sort -R)

    echo
    echo "Question #$num"
    PS3="${question//&quot;/\'} "

    select answer in "${answers[@]}"; do
        if [[ $answer == "$correct" ]]; then
            echo "Correct"
            break
        fi
        echo "Incorrect"
    done
}

get_quiz() {
    # this is where you'd do your curl call, but 
    # for now, the sample data is printed.
    cat << 'JSON'
    {
      "response_code": 0,
      "results": [
        {
          "category": "Entertainment: Television",
          "type": "multiple",
          "difficulty": "easy",
          "question": "Which company has exclusive rights to air episodes of the &quot;The Grand Tour&quot;?",
          "correct_answer": "Amazon",
          "incorrect_answers": [
            "Netflix",
            "BBC",
            "CCTV"
          ]
        },
        {
          "category": "Celebrities",
          "type": "multiple",
          "difficulty": "medium",
          "question": "How much weight did Chris Pratt lose for his role as Star-Lord in &quot;Guardians of the Galaxy&quot;?",
          "correct_answer": "60 lbs",
          "incorrect_answers": [
            "30 lbs",
            "50 lbs",
            "70 lbs"
          ]
        },
        {
          "category": "Animals",
          "type": "boolean",
          "difficulty": "easy",
          "question": "The Killer Whale is considered a type of dolphin.",
          "correct_answer": "True",
          "incorrect_answers": [
            "False"
          ]
        }
      ]
    }
JSON
}

main

假设您要遍历results数组中的每个元素，并将每个元素的correct_answer值分配给 shell 变量，并将incorrect_answers值分配给数组变量 in bash：

#!/bin/bash

data=file.json

unset results
eval "$( jq -r '@sh "results=\(.results|length)"' "$data" )"
if [ -z "$results" ]; then
    echo 'Failed to parse number of results' >&2
    exit 1
fi

for (( i = 0; i < results; ++i )); do
    unset correct_answer
    unset incorrect_answers

    eval "$(
        jq -r --argjson i "$i" '
            .results[$i] |
            @sh "correct_answer=\(.correct_answer)",
            @sh "incorrect_answers+=(\(.incorrect_answers[]))"' "$data"
    )"

    printf 'The correct answer for question %d was "%s"\n' \
        "$((i+1))" "$correct_answer"
    echo 'The question had the following incorrect answers:'
    printf '\t"%s"\n' "${incorrect_answers[@]}"
done

鉴于问题中的数据，这将输出

The correct answer for question 1 was "Amazon"
The question had the following incorrect answers:
        "Netflix"
        "BBC"
        "CCTV"
The correct answer for question 2 was "60 lbs"
The question had the following incorrect answers:
        "30 lbs"
        "50 lbs"
        "70 lbs"
The correct answer for question 3 was "True"
The question had the following incorrect answers:
        "False"

在每次迭代中，该jq工具用于提取resultsJSON 文档中数组的特定元素。它将数据格式化为一组 shell 分配。例如，当$i为 1 时，它将创建语句

correct_answer='60 lbs'
incorrect_answers+=('30 lbs')
incorrect_answers+=('50 lbs')
incorrect_answers+=('70 lbs')

然后，shell 将评估这些语句，从而创建变量correct_answer和数组incorrect_answers。