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Last data update: 2014.03.03

R: Create handler for processing JSON elements from a parser

basicJSONHandler

R Documentation

Create handler for processing JSON elements from a parser

Description

This function creates a handler object that is used to consume tokens/elements from a JSON parser and combine them into R objects.

This is slow relative to using C code because this is done in R and also we don't know the length of each object until we have consumed all its elements.

Usage

basicJSONHandler(default.size = 100, simplify = FALSE)

Arguments

`default.size`	the best guess as to the sizes of the different elements. This is used for preallocating space for elements
`simplify`	a logical value indicating whether to simplify arrays from lists to vectors if the elements are of compatible types.

Value

`update`	a function called with a JSON element and used to process that element and add it to the relevant R object
`value`	a function to retrieve the result after processing the JSON

Author(s)

Duncan Temple Lang

Examples

  h = basicJSONHandler()
  x = fromJSON("[1, 2, 3]", h)
  x
  h$value()

Results


R version 3.3.1 (2016-06-21) -- "Bug in Your Hair"
Copyright (C) 2016 The R Foundation for Statistical Computing
Platform: x86_64-pc-linux-gnu (64-bit)

R is free software and comes with ABSOLUTELY NO WARRANTY.
You are welcome to redistribute it under certain conditions.
Type 'license()' or 'licence()' for distribution details.

R is a collaborative project with many contributors.
Type 'contributors()' for more information and
'citation()' on how to cite R or R packages in publications.

Type 'demo()' for some demos, 'help()' for on-line help, or
'help.start()' for an HTML browser interface to help.
Type 'q()' to quit R.

> library(RJSONIO)
> png(filename="/home/ddbj/snapshot/RGM3/R_CC/result/RJSONIO/basicJSONHandler.Rd_%03d_medium.png", width=480, height=480)
> ### Name: basicJSONHandler
> ### Title: Create handler for processing JSON elements from a parser
> ### Aliases: basicJSONHandler
> ### Keywords: IO programming
> 
> ### ** Examples
> 
>   h = basicJSONHandler()
>   x = fromJSON("[1, 2, 3]", h)
>   x
[[1]]
[1] 1

[[2]]
[1] 2

[[3]]
[1] 3

>   h$value()
[[1]]
[1] 1

[[2]]
[1] 2

[[3]]
[1] 3

> 
> 
> 
> 
> 
> dev.off()
null device 
          1 
>