freeCodeCamp/curriculum/challenges/espanol/07-scientific-computing-with-python/learn-algorithm-design-by-building-a-shortest-path-algorithm/6559d70c5161b16ff1d6530d.md

id, title, challengeType, dashedName

id	title	challengeType	dashedName
6559d70c5161b16ff1d6530d	Step 54	20	step-54

--description--

Python provides a concise way to write if/else conditionals by using the ternary syntax:

val_1 if condition else val_2

The expression above evaluates to val_1 if condition is true, otherwise to val_2.

Delete your print call and create a variable called targets_to_print after your while loop. Use the ternary syntax to assign it [target] when target is truthy, and graph otherwise.

--hints--

You should delete your print call.

({ test: () => assert.isFalse( /print\s*\(\s*f("|')Unvisited:\s*\{\s*unvisited\s*\}\\nDistances:\s\{\s*distances\s*\}\\nPaths:\s\{\s*paths\s*\}\1\s*\)/.test(code)) })

You should create a variable called targets_to_print after your while loop.

({ test: () =>  {
    const shortest = __helpers.python.getDef(code, "shortest_path");
    const {function_body} = shortest;    
    assert(function_body.match(/unvisited\.remove\(\s*current\s*\).*^\s{4}targets_to_print\s*=/ms));
  }
})

You should use the ternary syntax to assign [target] when target is truthy, and graph otherwise to your targets_to_print variable.

({ test: () =>  {
    const shortest = __helpers.python.getDef(code, "shortest_path");
    const {function_body} = shortest;    
    assert(function_body.match(/unvisited\.remove\(\s*current\s*\).*^\s{4}targets_to_print\s*=\s*\[\s*target\s*\]\s+if\s+target\s+else\s+graph/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--    
    print(f'Unvisited: {unvisited}\nDistances: {distances}\nPaths: {paths}')

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