freeCodeCamp/curriculum/challenges/german/07-scientific-computing-with-python/learn-algorithm-design-by-building-a-shortest-path-algorithm/6557927ad11e58bf8c794b25.md

id, title, challengeType, dashedName

id	title	challengeType	dashedName
6557927ad11e58bf8c794b25	Step 55	20	step-55

--description--

Create a for loop to iterate over targets_to_print and print the following f-string: f'\n{start}-{node} distance: {distances[node]}\nPath: {" -> ".join(paths[node])}'.

--hints--

You should create a for loop to iterate over targets_to_print. Use node as the loop variable.

({ test: () =>  {
    const shortest = __helpers.python.getDef(code, "shortest_path");
    const {function_body} = shortest;    
    assert(function_body.match(/^(\s{4})for\s+node\s+in\s+targets_to_print\s*:/m));
  }
})

You should print the provided string inside your new for loop.

({ test: () =>  {
    const shortest = __helpers.python.getDef(code, "shortest_path");
    const {function_body} = shortest;    
    assert(function_body.match(/^(\s{4})for\s+node\s+in\s+targets_to_print\s*:\s*^\1\1print\s*\(\s*f("|')\\n\{\s*start\s*\}-\{\s*node\s*\}\sdistance:\s\{\s*distances\s*\[\s*node\s*\]\s*\}\\nPath:\s\{\s*(?=[^\1])("|')\s->\s\3\.join\s*\(\s*paths\s*\[\s*node\s*\]\s*\)\s*\}\2\s*\)/ms));
  }
})

--seed--

--seed-contents--

my_graph = {
    'A': [('B', 3), ('D', 1)],
    'B': [('A', 3), ('C', 4)],
    'C': [('B', 4), ('D', 7)],
    'D': [('A', 1), ('C', 7)]
}

def shortest_path(graph, start, target = ''):
    unvisited = list(graph)
    distances = {node: 0 if node == start else float('inf') for node in graph}
    paths = {node: [] for node in graph}
    paths[start].append(start)

    while unvisited:
        current = min(unvisited, key=distances.get)
        for node, distance in graph[current]:
            if distance + distances[current] < distances[node]:
                distances[node] = distance + distances[current]
                if paths[node] and paths[node][-1] == node:
                    paths[node] = paths[current][:]
                else:
                    paths[node].extend(paths[current])
                paths[node].append(node)
        unvisited.remove(current)
--fcc-editable-region--    
    targets_to_print = [target] if target else graph


shortest_path(my_graph, 'A')
--fcc-editable-region--