Question

我有一个巨大的json.gz文件，并且该文件已经转换为.json文件。我想问一下我们如何使用R读取.json文件中的前100条记录。非常感谢您的帮助。以下是示例代码：

library(jsonlite)
library(R.utils)
r=stream_in(file("yelp_academic_dataset_business.json"))

可以从链接中找到文件“ yelp_academic_dataset_business.json”： https://www.dropbox.com/s/gd1k41y9gbpfwq3/yelp_academic_dataset_business.json

Answer 1

使用来自原始链接的数据，@ Shree的建议很明确。首先，使用readLines下载所需数量的行：

dat <- readLines("https://uc385e5985dd32823a7dc6ba9b5e.dl.dropboxusercontent.com/cd/0/get/AhyCjVEm8yKnLz4w0-hZaW-titb8fOhQdMcwhTMF1_3i_iJ7DOqOU_KQRTtcvaFBaSTpAznh_6eq-vKAEiDkeVygMnRjThrnz0V5fyC4AURAcg/file?_download_id=9916801659220323334123287637995650900165723151388885263767035946&_notify_domain=www.dropbox.com&dl=1", n =4 )
# dat <- readLines("yelp_academic_dataset_business.json", n = 4)

现在创建一个“伪文本连接”，并将其传递给json解析器：

jsonlite::stream_in(textConnection(dat))
#  Imported 4 records. Simplifying...
#              business_id                                        full_address hours.Tuesday.close hours.Tuesday.open hours.Friday.close hours.Friday.open hours.Monday.close hours.Monday.open
# 1 vcNAWiLM4dR7D2nwwJ7nCA 4840 E Indian School Rd\nSte 101\nPhoenix, AZ 85018               17:00              08:00              17:00             08:00              17:00             08:00
# 2 UsFtqoBl7naz8AVUBZMjQQ                202 McClure St\nDravosburg, PA 15034                <NA>               <NA>               <NA>              <NA>               <NA>              <NA>
# 3 cE27W9VPgO88Qxe4ol6y_g             1530 Hamilton Rd\nBethel Park, PA 15234                <NA>               <NA>               <NA>              <NA>               <NA>              <NA>
# 4 HZdLhv6COCleJMo7nPl-RA               301 S Hills Vlg\nPittsburgh, PA 15241               21:00              10:00              21:00             10:00              21:00             10:00
#   hours.Wednesday.close hours.Wednesday.open hours.Thursday.close hours.Thursday.open hours.Sunday.close hours.Sunday.open hours.Saturday.close hours.Saturday.open  open
# 1                 17:00                08:00                17:00               08:00               <NA>              <NA>                 <NA>                <NA>  TRUE
# 2                  <NA>                 <NA>                 <NA>                <NA>               <NA>              <NA>                 <NA>                <NA>  TRUE
# 3                  <NA>                 <NA>                 <NA>                <NA>               <NA>              <NA>                 <NA>                <NA> FALSE
# 4                 21:00                10:00                21:00               10:00              18:00             11:00                21:00               10:00  TRUE
#                                                                                               categories        city review_count                     name neighborhoods  longitude state stars
# 1                                                                              Doctors, Health & Medical     Phoenix            9        Eric Goldberg, MD          NULL -111.98376    AZ   3.5
# 2                                                                                              Nightlife  Dravosburg            4             Clancy's Pub          NULL  -79.88693    PA   3.5
# 3                                                                           Active Life, Mini Golf, Golf Bethel Park            5 Cool Springs Golf Center          NULL  -80.01591    PA   2.5
# 4 Shopping, Home Services, Internet Service Providers, Mobile Phones, Professional Services, Electronics  Pittsburgh            3         Verizon Wireless          NULL  -80.05998    PA   3.5
#   latitude attributes.By Appointment Only attributes.Happy Hour attributes.Accepts Credit Cards attributes.Good For Groups attributes.Outdoor Seating attributes.Price Range
# 1 33.49931                           TRUE                    NA                              NA                         NA                         NA                     NA
# 2 40.35052                             NA                  TRUE                            TRUE                       TRUE                      FALSE                      1
# 3 40.35690                             NA                    NA                              NA                         NA                         NA                     NA
# 4 40.35762                             NA                    NA                              NA                         NA                         NA                     NA
#   attributes.Good for Kids     type
# 1                       NA business
# 2                       NA business
# 3                     TRUE business
# 4                       NA business

如何使用R读取json文件的前几条记录？

1 个答案: