背景
我将GTFS数据存储在本地mongodb数据库中。
calendar表看起来像
field | type
service_id | varchar
monday | int (0 or 1)
tuesday | int (0 or 1)
...
sunday | int (0 or 1)任务
我希望使用service_id中的rmongodb包来选择任何工作日(星期一到星期五)= 1的所有r。
在SQL中,这将类似于:SELECT service_id FROM calendar WHERE monday = 1 OR tuesday = 1 OR ... OR friday = 1
细节
当使用罗波蒙戈 GUI时,查询如下:
db.getCollection('calendar').find({"$or" :
[{'monday':1},
{'tuesday':1},
{'wednesday':1},
{'thursday':1},
{'friday':1}]
})返回8个文档(见图)

因此,在r中,我试图构造相同的or查询,返回相同的结果,但我没有任何运气。
library(rmongodb)
library(jsonlite)
## connect to db
mongo <- mongo.create()
mongo.is.connected(mongo)
db <- "temp"
## days for which I want a service:
serviceDays <- c("monday","tuesday","wednesday","thursday","friday")尝试0:
## create list as the 'query' condition
ls <- list("$or" =
list("monday" = 1L,
"tuesday" = 1L,
"wednesday" = 1L,
"thursday" = 1L,
"friday" = 1L))
services <- mongo.find.all(mongo, "temp.calendar", query=ls)
## returns error:
Error in mongo.find(mongo, ns, query = query, sort = sort, fields = fields, :
find failed with unknown error.尝试1:
## paste the string together
js <- paste0('{"', serviceDays, '":[',1L,']}', collapse=",")
js <- paste0('{"$or" :[', js, ']}')
## this string has been validated at jsonlint.com
bs <- mongo.bson.from.JSON(js)
## run query
services <- mongo.find.all(mongo, "temp.calendar", query=bs)
## result
> services
list() ## empty list
## manually writing the JSON string doesn't work either
# js <- '{"$or" : [{"monday":[1]},{"tuesday":[1]},{"wednesday":[1]},{"thursday":[1]},{"friday":[1]}]}'企图2:
## create the or condition using R code
l <- as.list(sapply(serviceDays, function(y) 1L))
bs <- mongo.bson.from.list(list("$or" = list(l)))
## run query
services <- mongo.find.all(mongo, "temp.calendar", query=bs)
## result
> length(services)
[1] 2 ## 2 documents returned返回的两份文件都是给service_id的,整个星期一,星期二,星期三,星期四,星期五= 1。也就是说,它似乎使用了AND子句,而不是OR。
企图3:
## deconstruct the JSON string (attempt 1)
js <- fromJSON(js, simplifyVector=FALSE)
bs <- mongo.bson.from.list(js)
## run query
services <- mongo.find.all(mongo, "temp.calendar", query=bs)
## result
> services
list() ## empty list我在R中的查询尝试有什么问题,它阻止了我在使用Robomongo时获得相同的8个文档?
发布于 2015-07-18 22:22:53
我的“尝试0”已经接近,但是我丢失了更多的list参数。
ls <- list("$or" = list(list("monday" = 1L),
list("tuesday" = 1L),
list("wednesday" = 1L),
list("thursday"= 1L),
list("friday" = 1L)))
## json string:
> toJSON(ls)
{"$or":[{"monday":[1]},{"tuesday":[1]},{"wednesday":[1]},{"thursday":[1]},{"friday":[1]}]}
## run query:
services <- mongo.find.all(mongo, "temp.calendar", query=ls)
## result
length(services)
[1] 8https://stackoverflow.com/questions/31491209
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