find minimum value of list in dictionary

Question

I've been stuck for hours please help me find a way to compare the keys in the queue to dictionary and finding the minimum value.

Below is the code I have so far. I try using min() but it doesnt work.

def find_min(label,queue): 
  
  for i in queue:
    for l in label:
      for s in label[i]:
        list1 = []
        return min(l[1])

bellow is the label and queue input

Answer 1

You can use the following.

Code

def find_min(labels, queue):
    # Sort labels dictionary  based upon last item in values list 
    # which will be a number (kv[1] is value list, kv[1][-1] is last value in list)
    sorted_labels = dict(sorted(labels.items(), key = lambda kv: kv[1][-1]))
    
    #  Get the keys in order from sorted_labels that are also in the queue
    options = [k for k in sorted_labels if k in queue]
    
    # Return the first one (will be the smallest)
    return options[0] if options else None

Test

print(find_min({"A" : [0], "B" : ["A",10], "C" : ["B",10], "D" : ["C",15]}, ["A", "D"]))  
# Output: A

print(find_min({"A" : [0], "B" : ["A",10], "C" : ["B",10], "D" : ["C",15]}, ["B", "C", "D"]))  
# Output: B

Simpler Alternative

def find_min(labels, queue):
    # Initialize min value
    k_min, v_min = None, None

    for k, v in labels.items():
        if k in queue:
            # Only check keys in queue
            if v_min is None or v[-1] < v_min:
                # Don't have a min yet, or less than current min
                v_min = v[-1]
                k_min = k
    return k_min

Test

print(find_min({"A" : [0], "B" : ["A",10], "C" : ["B",10], "D" : ["C",15]}, ["A", "D"]))  
# Output: A

print(find_min({"A" : [0], "B" : ["A",10], "C" : ["B",10], "D" : ["C",15]}, ["B", "C", "D"]))  
# Output: B

Using Poster's Code

def find_min(label,queue): 
    kmin = None
    value_min = None
    for l in label:
      if l in queue:
        value = label[l]
        n = len(value)
        last_value = value[n-1]
        if kmin is None or last_value < value_min:
            kmin = l
            value_min = last_value
    return kmin