Renumbering nodes in the network

In several circumstances it might be necessary to renumber the nodes in the network entirely or a sub-set of them.

The renumberNodes() method allows to undertake this operation, requiring the following arguments:

The network name (for example, stored in the variable named network_name), after connecting to the database (db).
The list of current node numbers.
The list of new node numbers in the same sequence.

The below script provides and example when passing a subset of existing nodes for renumbering, and obtaining the full list through a Python dictionary.

current_node_numbers = [1, 2, 3, 4, 5, 6, 7]
new_node_numbers = [7, 6, 5, 4, 3, 2, 1]

nodes_renum_dict = dict()
for node_old, node_new in zip(current_node_numbers, new_node_numbers):
    nodes_renum_dict[node_old] = node_new

lua_expr = "value(node.n)"
current_nodes = db.valueForNodes(network_name, lua_expr)

current_nodes_list = []
new_nodes_list = []
for node in current_nodes:
    current_nodes_list.append(node.n)
    try:
        new_nodes_list.append(nodes_renum_dict[node.n])
    except:  # in case of error, when the key is not in the dictionary
        new_nodes_list.append(node.n)  # uses the current node number

db.renumberNodes(network_name, current_nodes_list, new_nodes_list)

When using this method, the user should consider that the network will be modified and saved with the new numbering pattern.