我在主JSON文件中存储了大量对象。我想遍历该数组，获取每个对象，然后根据对象中的字段（在本例中为状态名称）将其附加到新文件中。换句话说，在一组包含许多状态的数据中，我想将其过滤到每个状态的文件中。
我正在使用现有的JQ表达式来仅过滤我实际需要的数据：
{ fipscode: .fipscode, level: .level, polid: .polid, polnum: .polnum, precinctsreporting: .precinctsreporting, precinctsreportingpct: .precinctsreportingpct, precinctstotal: .precinctstotal, raceid: .raceid, runoff: .runoff, statepostal: .statepostal, votecount: .votecount, votepct: .votepct, winner: .winner }
这是我输入的示例：
[
{ "ballotorder": 2, "candidateid": "9718", "delegatecount": 0, "description": null, "electiondate": "2018-08-28", "electtotal": 0, "electwon": 0, "fipscode": null, "first": "Doug", "id": "3015-polid-64364-state-AZ-1", "incumbent": true, "initialization_data": false, "is_ballot_measure": false, "last": "Ducey", "lastupdated": "2018-08-30T00:01:38.897Z", "level": "state", "national": true, "officeid": "G", "officename": "Governor", "party": "GOP", "polid": "64364", "polnum": "5554", "precinctsreporting": 1488, "precinctsreportingpct": 0.9993000000000001, "precinctstotal": 1489, "raceid": "3015", "racetype": "Primary", "racetypeid": "R", "reportingunitid": "state-AZ-1", "reportingunitname": null, "runoff": false, "seatname": null, "seatnum": null, "statename": "Arizona", "statepostal": "AZ", "test": false, "uncontested": false, "votecount": 355455, "votepct": 0.705493, "winner": true },
{ "ballotorder": 2, "candidateid": "21689", "delegatecount": 0, "description": null, "electiondate": "2018-08-28", "electtotal": 0, "electwon": 0, "fipscode": null, "first": "Ron", "id": "10046-polid-62557-state-FL-1", "incumbent": false, "initialization_data": false, "is_ballot_measure": false, "last": "DeSantis", "lastupdated": "2018-08-29T19:29:50.367Z", "level": "state", "national": true, "officeid": "G", "officename": "Governor", "party": "GOP", "polid": "62557", "polnum": "13918", "precinctsreporting": 5968, "precinctsreportingpct": 1.0, "precinctstotal": 5968, "raceid": "10046", "racetype": "Primary", "racetypeid": "R", "reportingunitid": "state-FL-1", "reportingunitname": null, "runoff": false, "seatname": null, "seatnum": null, "statename": "Florida", "statepostal": "FL", "test": false, "uncontested": false, "votecount": 913997, "votepct": 0.564728, "winner": true },
{ "ballotorder": 2, "candidateid": "45555", "delegatecount": 0, "description": null, "electiondate": "2018-08-28", "electtotal": 0, "electwon": 0, "fipscode": null, "first": "Rex", "id": "38538-polid-67011-state-OK-1", "incumbent": false, "initialization_data": false, "is_ballot_measure": false, "last": "Lawhorn", "lastupdated": "2018-08-29T02:44:44.610Z", "level": "state", "national": true, "officeid": "G", "officename": "Governor", "party": "Lib", "polid": "67011", "polnum": "40784", "precinctsreporting": 1951, "precinctsreportingpct": 1.0, "precinctstotal": 1951, "raceid": "38538", "racetype": "Runoff", "racetypeid": "L", "reportingunitid": "state-OK-1", "reportingunitname": null, "runoff": false, "seatname": null, "seatnum": null, "statename": "Oklahoma", "statepostal": "OK", "test": false, "uncontested": false, "votecount": 379, "votepct": 0.409287, "winner": false }
]
作为输出，我希望有一个Arizona.json仅包含来自该状态的项目，并且还进行了过滤以删除不需要的字段：
[
{ "fipscode": null, "level": "state", "polid": "64364", "polnum": "5554", "precinctsreporting": 1488, "precinctsreportingpct": 0.9993000000000001, "precinctstotal": 1489, "raceid": "3015", "runoff": false, "statepostal": "AZ", "votecount": 355455, "votepct": 0.705493, "winner": true }
]
...以及其他涉及的州（Florida.json和Oklahoma.json）。
这是我到目前为止拥有的bash和jq脚本：
cat master.json |
jq -cn --stream 'fromstream(1|truncate_stream(inputs))' |
jq -c '.statename as $state | {
fipscode: .fipscode,
level: .level,
polid: .polid,
polnum: .polnum,
precinctsreporting: .precinctsreporting,
precinctsreportingpct: .precinctsreportingpct,
precinctstotal: .precinctstotal,
raceid: .raceid,
runoff: .runoff,
statepostal: .statepostal,
votecount: .votecount,
votepct: .votepct,
winner: .winner
}'
我不知道怎么截取每一行，这样我就可以确定输出应该去哪里。这可能吗？
答案 0 :(得分：1)
您可以这样做：jq的一个副本从输入文件中拆分出数据项，然后另一个实例每个状态将这些数据项整理在一起，而bash提供了粘合。对于bash 4.2或更高版本，请参见以下示例（可能与4.1兼容，我需要检查）。
#!/usr/bin/env bash
case $BASH_VERSION in ''|[123].*|4.[01].*) echo "ERROR: Bash 4.2 required" >&2; exit 1;; esac
input_file=$1
[[ -s $input_file ]] || { echo "Usage: ${0##*/} input-file" >&2; exit 1; }
jq_split_script='
# modify this function to fit your needs
def relevantContentOnly:
{ fipscode, level, polid, polnum, precinctsreporting, precinctsreportingpct, precinctstotal, raceid, runoff, statepostal, votecount, votepct, winner };
.[] | [.statename, (relevantContentOnly | tojson)] | @tsv
'
# Use an associative array to map from state names to output FDs
declare -A out_fds=( )
# Read state / line-of-data pairs from our JQ script...
while IFS=$'\t' read -r state data; do
# If we don't already have a writer for the current state, start one.
if [[ ! ${out_fds[$state]} ]]; then
exec {new_fd}> >(jq -n '[inputs]' >"$state.json")
out_fds[$state]=$new_fd
fi
# Regardless, send the data to the FD we have for this state
printf '%s\n' "$data" >&${out_fds[$state]}
done < <(jq -rc "$jq_split_script" <"$input_file") # ...running the JQ script above.
# close output FDs, so the JQ instances all flush
for fd in "${!out_fds[@]}"; do
exec {fd}>&-
done
答案 1 :(得分：1)
这是一个简单的解决方案，可搭载您的入门知识：
< master.json jq -cn --stream 'fromstream(1|truncate_stream(inputs))' |
jq -cr '.statename, {
fipscode,
level,
polid,
polnum,
precinctsreporting,
precinctsreportingpct,
precinctstotal,
raceid,
runoff,
statepostal,
votecount,
votepct,
winner
}' | while read -r statename && read -r object
do
echo "$object" >> "$statename.json"
done
请注意，这会将对象附加到任何现有的“ $ statename.json”文件中。
使用您的[原始]示例数据，以上代码会生成Arizona.json，Florida.json和Oklahoma.json
如果使用echo的开销比较大，则可以使用awk：
awk '
fn!="" {print > fn; fn=""; next}
{fn=$0 ".json";
if (fns[fn]!=1){fns[fn]=1; print fn > "filenames.txt"}}'
由于您希望这些文件包含对象数组，因此可以使用jq -s获得最终结果。我可能会在while循环内收集文件名（天真，例如echo "$statename.json" >> filenames.txt），然后使用sponge：
sort -u filenames.txt |
while read -r fn ; do
jq -s . "$fn" | sponge "$fn"
done