使用jq选择对象时出现意外结果

Posted 2021-04-01

当我将主体添加到输出列表时，会输出一些错误的名称。我希望在两个例子中只输出nfl subreddit的名称。功能还是错误？我怎样才能输出subreddit nfl的元组？

文件：

{"author":"403and780","author_flair_css_class":"NHL-EDM4-sheet1-col01-row17","author_flair_text":"EDM - NHL","body":"Don't get why we do this but can't have a Grey Cup GDT.","can_gild":true,"controversiality":0,"created_utc":1517788800,"distinguished":null,"edited":false,"gilded":0,"id":"dtqrsn6","is_submitter":false,"link_id":"t3_7v9yqa","parent_id":"t3_7v9yqa","permalink":"/r/hockey/comments/7v9yqa/game_thread_super_bowl_lii_philadelphia_eagles_vs/dtqrsn6/","retrieved_on":1518931297,"score":2,"stickied":false,"subreddit":"hockey","subreddit_id":"t5_2qiel","subreddit_type":"public"}    
{"author":"kygiacomo","author_flair_css_class":null,"author_flair_text":null,"body":"lol missed the extra wtf","can_gild":true,"controversiality":0,"created_utc":1517788800,"distinguished":null,"edited":false,"gilded":0,"id":"dtqrsn7","is_submitter":false,"link_id":"t3_7vad8n","parent_id":"t3_7vad8n","permalink":"/r/nfl/comments/7vad8n/super_bowl_lii_game_thread_philadelphia_eagles/dtqrsn7/","retrieved_on":1518931297,"score":2,"stickied":false,"subreddit":"nfl","subreddit_id":"t5_2qmg3","subreddit_type":"public"}    
{"author":"shitpostlord4321","author_flair_css_class":null,"author_flair_text":null,"body":"I really hope we get Bleeding Edge before we get the all new all different armor. ","can_gild":true,"controversiality":0,"created_utc":1517788800,"distinguished":null,"edited":false,"gilded":0,"id":"dtqrsn8","is_submitter":false,"link_id":"t3_7v7whz","parent_id":"t3_7v7whz","permalink":"/r/marvelstudios/comments/7v7whz/a_great_new_look_at_iron_mans_avengers_infinity/dtqrsn8/","retrieved_on":1518931297,"score":1,"stickied":false,"subreddit":"marvelstudios","subreddit_id":"t5_2uii8","subreddit_type":"public"}
{"author":"namohysip","author_flair_css_class":null,"author_flair_text":null,"body":"Maybe. I mostly am just doing this to get a story out, and itu2019s a huge one, so Iu2019m not sure that Iu2019ll be making another fic for many more months. I guess Pokemon Mystery Dungeon just isnu2019t as popular with the older demographics of AO3.","can_gild":true,"controversiality":0,"created_utc":1517788800,"distinguished":null,"edited":false,"gilded":0,"id":"dtqrsn9","is_submitter":true,"link_id":"t3_7v9psr","parent_id":"t1_dtqrm3t","permalink":"/r/FanFiction/comments/7v9psr/how_do_you_deal_with_bad_reviews/dtqrsn9/","retrieved_on":1518931297,"score":1,"stickied":false,"subreddit":"FanFiction","subreddit_id":"t5_2r5kb","subreddit_type":"public"}
{"author":"SDsc0rch","author_flair_css_class":null,"author_flair_text":null,"body":"if it rates an upvote, I'll click it - I'm not gonna click on low quality      
not gonna apologize for it either ","can_gild":true,"controversiality":0,"created_utc":1517788800,"distinguished":null,"edited":false,"gilded":0,"id":"dtqrsna","is_submitter":false,"link_id":"t3_7vaam4","parent_id":"t3_7vaam4","permalink":"/r/The_Donald/comments/7vaam4/daily_reminderif_you_see_any_gray_arrows_on_the/dtqrsna/","retrieved_on":1518931297,"score":4,"stickied":false,"subreddit":"The_Donald","subreddit_id":"t5_38unr","subreddit_type":"public"}
{"author":"scarletcrawford","author_flair_css_class":null,"author_flair_text":null,"body":"Honestly, I wanted Takeshi to stay with Poe, but to each their own ship, I guess.","can_gild":true,"controversiality":0,"created_utc":1517788800,"distinguished":null,"edited":false,"gilded":0,"id":"dtqrsnb","is_submitter":false,"link_id":"t3_7upyc0","parent_id":"t1_dtppyry","permalink":"/r/alteredcarbon/comments/7upyc0/season_1_series_discussion/dtqrsnb/","retrieved_on":1518931297,"score":2,"stickied":false,"subreddit":"alteredcarbon","subreddit_id":"t5_3bzvp","subreddit_type":"public"}
{"author":"immortalis","author_flair_css_class":"vikings","author_flair_text":"Vikings","body":"The ghost of MN kickers will haunt this game.","can_gild":true,"controversiality":0,"created_utc":1517788800,"distinguished":null,"edited":false,"gilded":0,"id":"dtqrsnc","is_submitter":false,"link_id":"t3_7vad8n","parent_id":"t3_7vad8n","permalink":"/r/nfl/comments/7vad8n/super_bowl_lii_game_thread_philadelphia_eagles/dtqrsnc/","retrieved_on":1518931297,"score":2,"stickied":false,"subreddit":"nfl","subreddit_id":"t5_2qmg3","subreddit_type":"public"}
{"author":"KryptoFreak405","author_flair_css_class":"48","author_flair_text":"","body":"His original backstory had him training to be an Imperial officer until a commanding officer ordered him to transport a shipment of slaves. He refused, freed the slaves, one of which was Chewie, and defected to become a smuggler","can_gild":true,"controversiality":0,"created_utc":1517788800,"distinguished":null,"edited":false,"gilded":0,"id":"dtqrsnd","is_submitter":false,"link_id":"t3_7vanzc","parent_id":"t1_dtqr5q5","permalink":"/r/StarWars/comments/7vanzc/solo_a_star_wars_story_big_game_tv_spot/dtqrsnd/","retrieved_on":1518931297,"score":1102,"stickied":false,"subreddit":"StarWars","subreddit_id":"t5_2qi4s","subreddit_type":"public"}
{"author":"thwinks","author_flair_css_class":null,"author_flair_text":null,"body":"Oh. TIL","can_gild":true,"controversiality":0,"created_utc":1517788800,"distinguished":null,"edited":false,"gilded":0,"id":"dtqrsne","is_submitter":false,"link_id":"t3_7v8o0z","parent_id":"t1_dtqg97a","permalink":"/r/gifs/comments/7v8o0z/silly_walk_champion/dtqrsne/","retrieved_on":1518931297,"score":2,"stickied":false,"subreddit":"gifs","subreddit_id":"t5_2qt55","subreddit_type":"public"}
{"author":"Mimi108","author_flair_css_class":"lions","author_flair_text":"Lions","body":"The Big. The Dick. The Nick. ","can_gild":true,"controversiality":0,"created_utc":1517788800,"distinguished":null,"edited":false,"gilded":0,"id":"dtqrsnf","is_submitter":false,"link_id":"t3_7vad8n","parent_id":"t3_7vad8n","permalink":"/r/nfl/comments/7vad8n/super_bowl_lii_game_thread_philadelphia_eagles/dtqrsnf/","retrieved_on":1518931297,"score":2,"stickied":false,"subreddit":"nfl","subreddit_id":"t5_2qmg3","subreddit_type":"public"}

代码示例1，工作正常：

$ cat head_rc.txt | jq -r 'select(.subreddit=="nfl") .author'
kygiacomo
immortalis
Mimi108

代码示例2，这对我来说是错误的或意外的：

$ cat head_rc.txt | jq -r 'select(.subreddit=="nfl") .body, .author'
403and780
lol missed the extra wtf
kygiacomo
shitpostlord4321
namohysip
SDsc0rch
scarletcrawford
The ghost of MN kickers will haunt this game.
immortalis
KryptoFreak405
thwinks
The Big. The Dick. The Nick. 
Mimi108

不幸的是，你可以看到作者403and780评论了一个曲棍球subreddit，而不是nfl。

答案

jq解决方案：

jq -r 'select(.subreddit == "nfl") as $o | $o.body, $o.author' head_rc.txt

• ... as $o - 将过滤后的对象分配给变量o

输出：

lol missed the extra wtf
kygiacomo
The ghost of MN kickers will haunt this game.
immortalis
The Big. The Dick. The Nick. 
Mimi108

另一答案

一旦我得到正确的语法，还需要添加流媒体。

一些好消息 - 您不需要使用所谓的“流解析器”，因为您的输入已被切断。仅当输入具有一个或多个单独的巨大JSON实体时才需要“流解析器”，而您有一个（长）小JSON对象流。

附：

正如Charles Duffy所说，选择问题的最简单方法是使用括号

jq -r 'select(.subreddit=="nfl") | (.body, .author)' input.json

如果CSV或TSV有意义，则将括号更改为括号，并粘贴@csv或@tsv，例如

select(.subreddit=="nfl") | [.body, .author] | @tsv