LOad packages

library(tidyverse)

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library(igraph)                    # This is the package to analyze the network

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library(visNetwork)                # Creates visualizations of the network
library(DT)
library(plotly)

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1. Read the data into links and nodes, and create the network in igraph with graph_from_data_frame().
   
2. Find the density of the network.
   
3. Make a histogram of the distances in the network.
   
4. Find the legnth of the diameter of the network.
   
5. Mutate the following into the nodes data: label, title, degree, and set value = degree.
   
6. Mutate betweenness into the links data, and set it to value.
   
7. Create a diagram with visNetwork, with a title and options set for a menu and highlightNearest.
   
8. Find the communities in the network, mutate a group column in the nodes data, and create another diagram displaying the colored groups.

Read data

sept11_nodes <- read_csv("Sept11_nodes.csv")

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sept11_links <- read_csv("Sept11_links.csv")

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Create network

sept11_network <- graph_from_data_frame(sept11_links,
                                        vertices= sept11_nodes, 
                                        directed = F)

Find network density

sept11_network %>% 
  edge_density()

## [1] 0.07985193

Make a histogram of distances

sept11_network %>% 
  distances() %>% 
  as.vector() %>%              # these two lines convert the distances matrix
  as_tibble() %>%              # to something plotly can graph
  plot_ly(x = ~value) %>% 
  add_histogram()

## Warning: Calling `as_tibble()` on a vector is discouraged, because the behavior is likely to change in the future. Use `enframe(name = NULL)` instead.
## This warning is displayed once per session.

Network length diameter

sept11_network %>% 
  get_diameter() %>% 
  length()

## [1] 6

Add info to nodes

sept11_nodes <- sept11_nodes %>% 
  mutate(label= name) %>% 
  mutate(title= name) %>% 
  mutate(degree= degree(sept11_network)) %>% 
  mutate(value= degree)

sept11_nodes

Add betweenness to links

sept11_links<- sept11_links %>% 
  mutate(betweenness= edge_betweenness(sept11_network)) %>% 
  mutate(value= betweenness)
sept11_links

Create network diagram

visNetwork(sept11_nodes, 
           sept11_links, 
           main = "Network of 9/11 Terrorists") %>% 
  visIgraphLayout(layout = "layout_nicely") %>% 
  visOptions(highlightNearest = T, nodesIdSelection = T)

Communities

sept11_nodes <- sept11_nodes %>% 
  mutate(group= membership(infomap.community(sept11_network))) 
sept11_nodes

Network diagram with communities

visNetwork(sept11_nodes, 
           sept11_links, 
           main = "Network of 9/11 Terrorists") %>% 
  visIgraphLayout(layout = "layout_nicely") %>% 
  visOptions(highlightNearest = T, nodesIdSelection = T, selectedBy = "group")