Loading Neo4j Data into R

Question

I'm trying to access my Neo4j data directly from R to do some network analysis

I have already read this: Use neo4j with R

So I tried using their code:

#install.packages('RCurl')
#install.packages('RJSONIO')

library('bitops')
library('RCurl')
library('RJSONIO')

query <- function(querystring) {
  h = basicTextGatherer()
  curlPerform(url="myhost:7474/db/data/ext/CypherPlugin/graphdb/execute_query",
    postfields=paste('query',curlEscape(querystring), sep='='),
    writefunction = h$update,
    verbose = FALSE
  )           
  result <- fromJSON(h$value())
  #print(result)
  data <- data.frame(t(sapply(result$data, unlist)))
  print(data)
  names(data) <- result$columns

}

q <-"start a = node(50) match a-->b RETURN b"
 data <- query(q)
 print(data)

However all I get is:

data frame with 0 columns and 1 rows + print(data) NULL

am I doing something wrong?

Nicole White · Answer 1 · 2014-07-23T20:41:40.867

That function is meant for returning tabular data, whereas you are returning a node. Hence the data frame error. There are also several things wrong with that function; it cannot return 1-column data and it has no NULL handling. Consider using the RNeo4j driver here:

http://nicolewhite.github.io/RNeo4j/

library(RNeo4j)
graph = startGraph("http://localhost:7474/db/data/")
query = "MATCH (n:`layer_1_SB`)-[r]-> (m) WHERE m:layer_2_SB RETURN n.userid, m.userid"
data = cypher(graph, query)
write.table(data, file = "filename.file")

score 1 · Accepted Answer · answered Jul 23 '14 at 20:17

So I fixed my problem. This is how the new code looks like:

#install.packages('RCurl')
#install.packages('RJSONIO')

library('bitops')
library('RCurl')
library('RJSONIO')

query <- function(querystring) {
  h = basicTextGatherer()
  curlPerform(url="myhost:7474/db/data/cypher",
    postfields=paste('query',curlEscape(querystring), sep='='),
    writefunction = h$update,
    verbose = FALSE
  )           
  result <- fromJSON(h$value())
  #print(result)
  data <- data.frame(t(sapply(result$data, unlist)))
  print(data)
  names(data) <- result$columns
  data

}

q <-"MATCH (n:`layer_1_SB`)-[r]-> (m) WHERE m:layer_2_SB RETURN n.userid, m.userid"
 data <- query(q)
 head(data)
 dim(data)
 names(data)
 write.table(data, file = "/home/angello-maggio/data2.dat", append=FALSE,quote=FALSE,sep=" ",eol="\n", na="NA", dec=".", row.names=FALSE)

As you can see if you're using neo4j 2.x you should use the path /db/data/cypher instead of /db/data/ext/CypherPlugin/graphdb/execute_query also I had forgotten to return data, and was returning names(data) instead.

Also nulls might happen if your query is wrong. Hope this helps someone who had my problem too!

Loading Neo4j Data into R

2 Answers2