Dictionary

#!/bin/bash
# Declare a dictionary.
declare -A Host
Host=( [node1]='10.1.1.11' [node2]='10.1.1.12' [node3]='10.1.1.13' [node4]='10.1.1.14' )

# Traversing dictionary values.
for node_ip in ${Host[@]};
do
  echo "One IP of these hosts is ${node_ip} .";
done

# Traversing dictionary keys.
for node in ${!Host[@]};
do
  echo "One hostname of these hosts is: ${node}. ";
done

# Traverse keys and values at the same time.
for node in ${!Host[@]};
do
  echo "Hostname: ${node}, IP: ${Host[${node}]}. "
done

# Get the length of this dictionary.
echo "The length of this dictionary is ${#Host[@]}. "

# Append a key and a value.
Host[node5]='10.1.1.15'
echo "The value of new dictionary is: ${Host[@]}. "
echo "The length of dictionary is: ${#Host[*]}. "

# Modify a value of the dictionary .
Host[node1]='10.1.1.111'
echo "The value of new dictionary is: ${Host[@]}. "