r - delete vertices using which on igraph vector -

i trying delete vertices graph in igraph , not working. think issue might with

> toosmall <- which(v(g)$coreness.all <= 5) 

as appears return integer(0).

how can remove vertices graph below?

> graph.coreness(g)   [1]  1 19  1  3 17 19  5 19 19 19 19  7 19 18 17 12 12 19 19 17 16 19  3  3  7 12 18  4  5 12 12  3  1  6 19  5 19 19  3 19 17 17 19 19  5  1  1  7  8 19  1  2   [53]  7  3 17  5  4 19  3 16  1  3 13  3 14 10 10 13  8 18 18 12  6 10 12 14 11 16 12  7  5  7  5 10 15 16 10  3  5  5 16 16 16 13 16 16 16 16 16 15 10  6  2  1  [105] 14 16 16 11  5 11 16 11 10 16  2 14  7  8  1 10 12 12 12 19  8 10  7  5 13  3 19 16  3  4  4 19 13  7 16 13 11 13 15 13  3  2  3  3  2  9 14 16 16 14 16 13  [157] 13 15 13 11 12 11  1  1 11 19  7  3 19  3  7  5 19 19 19 19 19 19 19 18 19 11 13 17  4 19 16 19 11  9  9 12 19 16 11 19  4  7  4 19  6  6  9  2 15  8  7  5  [209] 10  7  3 10  6  8  4 11 13  2  7  6  7  6  9  4  3  3 13  3 13  9  4 13  5  5  6  6  6 14  8  2  5  7  7 14  7  9  6  8 12  1  1  1 14  1 10  8 16  2  6  9  [261]  3  7 14 16 15  2  5  1  4  7 17  7  6  4 11  8  9 15  4  4 15  1  5  5  3  6  1  2  2  4  4  1  5  1  6  1  5  5  3  2  3  3  6  6  6  3  2  8  5  6  3  3  [313]  2  1  5  2 12  3  1  6  1  2  5  2  1  3  1  1  8  2  3 > toosmall <- which(v(g)$coreness.all <= 5) > delete.vertices(g,toosmall) igraph u--- 331 2771 --  + attr: color (v/c), shape (v/c), size (v/c), opacity (v/c), image file (v/c), visibility (v/c), label (v/c), label fill color (v/c), label   position (v/c), tooltip (v/c), layout order (v/c), x (v/c), y (v/c), locked? (v/c), polar r (v/c), polar angle (v/c), degree (v/c), in-degree   (v/c), out-degree (v/c), betweenness centrality (v/c), closeness centrality (v/c), eigenvector centrality (v/c), pagerank (v/c), clustering   coefficient (v/c), reciprocated vertex pair ratio (v/c), id (v/c), dynamic filter (v/c), add own columns here (v/c), followed (v/c),   followers (v/c), tweets (v/c), favorites (v/c), time zone utc offset (seconds) (v/c), description (v/c), location (v/c), web (v/c), time zone   (v/c), joined twitter date (utc) (v/c), user of interest? (v/c), custom menu item text (v/c), custom menu item action (v/c), id (v/c), color   (e/c), width (e/c), style (e/c), opacity (e/c), visibility (e/c), label (e/c), label text color (e/c), label font size (e/c), reciprocated?   (e/c), id (e/c), dynamic filter (e/c), add own columns here (e/c), relationship (e/c), relationship date (utc) (e/c), tweet (e/c), urls   in tweet (e/c), domains in tweet (e/c), hashtags in tweet (e/c), tweet date (utc) (e/c), twitter page tweet (e/c), latitude (e/c),   longitude (e/c), imported id (e/c), in-reply-to tweet id (e/c), edge weight (e/c) > g igraph u--- 331 2771 --  + attr: color (v/c), shape (v/c), size (v/c), opacity (v/c), image file (v/c), visibility (v/c), label (v/c), label fill color (v/c), label   position (v/c), tooltip (v/c), layout order (v/c), x (v/c), y (v/c), locked? (v/c), polar r (v/c), polar angle (v/c), degree (v/c), in-degree   (v/c), out-degree (v/c), betweenness centrality (v/c), closeness centrality (v/c), eigenvector centrality (v/c), pagerank (v/c), clustering   coefficient (v/c), reciprocated vertex pair ratio (v/c), id (v/c), dynamic filter (v/c), add own columns here (v/c), followed (v/c),   followers (v/c), tweets (v/c), favorites (v/c), time zone utc offset (seconds) (v/c), description (v/c), location (v/c), web (v/c), time zone   (v/c), joined twitter date (utc) (v/c), user of interest? (v/c), custom menu item text (v/c), custom menu item action (v/c), id (v/c), color   (e/c), width (e/c), style (e/c), opacity (e/c), visibility (e/c), label (e/c), label text color (e/c), label font size (e/c), reciprocated?   (e/c), id (e/c), dynamic filter (e/c), add own columns here (e/c), relationship (e/c), relationship date (utc) (e/c), tweet (e/c), urls   in tweet (e/c), domains in tweet (e/c), hashtags in tweet (e/c), tweet date (utc) (e/c), twitter page tweet (e/c), latitude (e/c),   longitude (e/c), imported id (e/c), in-reply-to tweet id (e/c), edge weight (e/c) > g <- delete.vertices(g,toosmall) > g igraph u--- 331 2771 --  + attr: color (v/c), shape (v/c), size (v/c), opacity (v/c), image file (v/c), visibility (v/c), label (v/c), label fill color (v/c), label   position (v/c), tooltip (v/c), layout order (v/c), x (v/c), y (v/c), locked? (v/c), polar r (v/c), polar angle (v/c), degree (v/c), in-degree   (v/c), out-degree (v/c), betweenness centrality (v/c), closeness centrality (v/c), eigenvector centrality (v/c), pagerank (v/c), clustering   coefficient (v/c), reciprocated vertex pair ratio (v/c), id (v/c), dynamic filter (v/c), add own columns here (v/c), followed (v/c),   followers (v/c), tweets (v/c), favorites (v/c), time zone utc offset (seconds) (v/c), description (v/c), location (v/c), web (v/c), time zone   (v/c), joined twitter date (utc) (v/c), user of interest? (v/c), custom menu item text (v/c), custom menu item action (v/c), id (v/c), color   (e/c), width (e/c), style (e/c), opacity (e/c), visibility (e/c), label (e/c), label text color (e/c), label font size (e/c), reciprocated?   (e/c), id (e/c), dynamic filter (e/c), add own columns here (e/c), relationship (e/c), relationship date (utc) (e/c), tweet (e/c), urls   in tweet (e/c), domains in tweet (e/c), hashtags in tweet (e/c), tweet date (utc) (e/c), twitter page tweet (e/c), latitude (e/c),   longitude (e/c), imported id (e/c), in-reply-to tweet id (e/c), edge weight (e/c) > toosmall integer(0) 

i think have define toosmall as:

toosmall <- which(graph.coreness(g) <= 5) 

here worked example using constructed graph, use lower threshold deletion criterion:

# create graph g <- graph.ring(10) g <- add.edges(g, c(1,2, 2,3, 1,3)) graph.coreness(g)  # identify vertices coresness <= threshold toosmall <- which(graph.coreness(g) <= 2)  # delete vertices , plot gp <- delete.vertices(g, toosmall) plot(gp)