Execute a query with jq

jq is meant to work with the high level interface in this package. jq also provides access to the low level interface in which you can use jq query strings just as you would on the command line. Output gets class of json, and pretty prints to the console for easier viewing. jqr doesn't do pretty printing.

Usage

jq(x, ...)

# S3 method for jqr
jq(x, ...)

# S3 method for character
jq(x, ..., flags = jq_flags())

# S3 method for json
jq(x, ..., flags = jq_flags())

# S3 method for connection
jq(x, ..., flags = jq_flags(), out = NULL)

Arguments

x

json object or character string with json data. this can be one or more valid json objects

...

character specification of jq query. Each element in ... will be combined with " | ", which is convenient for long queries.

flags

See jq_flags

out

a filename, callback function, connection object to stream output. Set to `NULL` to buffer all output and return a character vector.

See also

peek

Examples

'{"a": 7}' %>%  do(.a + 1)
#> 8
'[8,3,null,6]' %>% sortj
#> [
#>     null,
#>     3,
#>     6,
#>     8
#> ]

x <- '[{"message": "hello", "name": "jenn"},
  {"message": "world", "name": "beth"}]'
jq(index(x))
#> [
#>     {
#>         "message": "hello",
#>         "name": "jenn"
#>     },
#>     {
#>         "message": "world",
#>         "name": "beth"
#>     }
#> ]

jq('{"a": 7, "b": 4}', 'keys')
#> [
#>     "a",
#>     "b"
#> ]
jq('[8,3,null,6]', 'sort')
#> [
#>     null,
#>     3,
#>     6,
#>     8
#> ]

# many json inputs
jq(c("[123, 456]", "[77, 88, 99]", "[41]"), ".[]")
#> [
#>     123,
#>     456,
#>     77,
#>     88,
#>     99,
#>     41
#> ]
# Stream from connection
tmp <- tempfile()
writeLines(c("[123, 456]", "[77, 88, 99]", "[41]"), tmp)
jq(file(tmp), ".[]")
#> [
#>     123,
#>     456,
#>     77,
#>     88,
#>     99,
#>     41
#> ]

if (FALSE) {
# from a url
x <- 'http://jeroen.github.io/data/diamonds.json'
jq(url(x), ".[]")

# from a file
file <- file.path(tempdir(), "diamonds_nd.json")
download.file(x, destfile = file)
jq(file(file), ".carat")
jq(file(file), "select(.carat > 1.5)")
jq(file(file), 'select(.carat > 4 and .cut == "Fair")')
}