[igraph] induced.subgraph in for

[Roney Fraga Souza]

Hello everyone, 

I have a network where the papers are nodes and citations are links. To generate a network I do:

#------------------------------

# begin code

#------------------------------

# Download the data

# the file 'db.rds' has 38.6 MB

# https://dl.dropboxusercontent.com/u/61883020/db.rds

url  <- "https://dl.dropboxusercontent.com/u/61883020/db.rds"

download.file(url, destfile= "./db.rds",method="curl")

library(igraph)

db <- readRDS("db.rds")

lapply(db, names)

lapply(db, dim)

db[[1]][1:6,c('name','PY')]

db[[2]][1:6,]

net <- graph.data.frame(

                        db[[2]], 

                        directed=TRUE,

                        vertices=db[[1]]

                        )

# > print(net)

# IGRAPH DN-- 29168 111039 --

# + attr: name (v/c), PT (v/c), AU (v/c), BA (v/c), BE (v/c), GP

# | (v/c), AF (v/c), BF (v/c), CA (v/c), TI (v/c), SO (v/c), SE

# | (v/c), BS (v/c), LA (v/c), DT (v/c), CT (v/c), CY (v/c), CL

# | (v/c), SP (v/c), HO (v/c), DE (v/c), ID (v/c), AB (v/c), C1

# | (v/c), RP (v/c), EM (v/c), RI (v/c), OI (v/c), FU (v/c), FX

# | (v/c), CR (v/c), NR (v/n), TC (v/n), Z9 (v/n), PU (v/c), PI

# | (v/c), PA (v/c), SN (v/c), EI (v/c), BN (v/c), J9 (v/c), JI

# | (v/c), PD (v/c), PY (v/n), VL (v/c), IS (v/c), PN (v/c), SU

# | (v/c), SI (v/c), MA (v/c), BP (v/c), EP (v/c), AR (v/c), DI

# | (v/c), D2 (v/c), PG (v/n), WC (v/c), SC (v/c), GA (v/c), UT

# | (v/c), PM (v/n)

# + edges (vertex names):

# Error in seq_len(no) : argument must be coercible to non-negative integer

#------------------------------

# end code

#------------------------------

I do not know the reason for this message: 

"Error in seq_len(no) : argument must be coercible to non-negative integer".

But this is not the main point (maybe).

My network is built by published articles from 1904 until 2014. I would like to create a cumulative network for each year. For example:

#------------------------------

# begin code

#------------------------------

# V(net)$PY = publication year

#

net.until.1960 <- induced.subgraph(net, V(net)$PY<=1960)

net.until.1970 <- induced.subgraph(net, V(net)$PY<=1970)

net.until.1980 <- induced.subgraph(net, V(net)$PY<=1980)

net.until.1990 <- induced.subgraph(net, V(net)$PY<=1990)

#------------------------------

# end code

#------------------------------

But when I run the last code in a loop only the first result is returned.

#------------------------------

# begin code

#------------------------------

# get network

pegar.subgrafo <- function(x,i){induced.subgraph(x, V(x)$PY<=i)}

# empty list

netl <- list()

# generate networks for years

for(i in min(V(net)$PY):max(V(net)$PY)){

    netl[[i]] <- pegar.subgrafo(net,i)

}

# delete NULL 

netl <- netl[ -(which(sapply(netl,is.null), arr.ind=TRUE))]

netl

#------------------------------

# end code

#------------------------------

Thanks for any sugestion.

regards,

Roney

#------------------------------

> sessionInfo()

R version 3.2.1 (2015-06-18)

Platform: x86_64-apple-darwin13.4.0 (64-bit)

Running under: OS X 10.10.4 (Yosemite)

locale:

[1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8

attached base packages:

[1] stats     graphics  grDevices utils     datasets  methods   base

other attached packages:

[1] igraph_1.0.1   vimcom_1.2-6   setwidth_1.0-4 colorout_1.1-1

loaded via a namespace (and not attached):

[1] magrittr_1.5 tools_3.2.1

#------------------------------