CODEWITHSUNDEEP
pythonpython-3.xdictionary
Mike.G
Mike.G

Reputation: 443

Multiple value search in dictionary keys

Iterating over dict values - related to this question:

def bla(self,x,y)   
    for i in self.DataBase.keys():
        for x,y in self.DataBase[i]:
            if x == dept and y == year:
                return self.DataBase[i]

This is more of the idea that I am trying to achieve, how do I take a key and search for n values in the key, then return the key if the values are in the key

Upvotes: 6

Views: 3291

Answers (3)

buydadip
buydadip

Reputation: 9427

You may use the built-in map() to set the x and y variables.

def bla(self,x,y) :
    for key in self.DataBase :
        x,y = map(float, self.DataBase[key])
        if x == dept and y == year:
            return key

If you prefer using items(), you may do the following as well (equally valid):

def bla(self,x,y):
    for key, val in self.DataBase.items():
        x, y = map(float, val)
        if x == dept and y == year:
            return key

Here's yet another way of doing it without map(), this gives you the advantage of unpacking the tuples while iterating over the dict:

 def bla(self,x,y):
    for key, (x, y) in self.DataBase.items():
        if x == dept and y == year:
            return key

You may also write the above as so, using list comprehension, although I would say the one above is preferable:

def bla(self,x,y):
    found = {key for key, (x, y) in self.DataBase.items() if x==dept and y==year}
    found = ''.join(num) #joins set into string
    return found

The following all work for Python 3, which I assume is what you want since one of your tags are Python 3.x

Upvotes: 1

dopstar
dopstar

Reputation: 1488

Below, the method bla returns the database key if x and y match the first and second elements of the tuple (of whatever length), respectively, that correspond to the key:

def bla(self, x, y)   
    for key, value in self.DataBase.iteritems():
        if (x, y) == value[:2]:
            return key

And now below, the method bla returns the database key if the database value which is a tuple contains both x and y:

def bla(self, x, y)   
    for key, value in self.DataBase.iteritems():
        if x in value and y in value:
            return key

Upvotes: 3

rchang
rchang

Reputation: 5236

Since you said "return the key" in the question, I assume you actually want to isolate the keys in the dictionary whose values match some set of search parameters (the code fragment you posted returns the values, not the keys). Assuming self.Database is a dictionary, you could extract the keys as a list comprehension with something like the following:

def getMatchingKeys(self, x, y):
  '''Extract keys whose values contain x and y (position does not matter)'''
  return [i for i in self.Database if x in self.Database[i] and y in self.Database[i]]

Keys whose values contain both x and y anywhere in the tuple will be returned. If you need to match specific positions in the tuple, the conditional inside the comprehension can be changed to something like if x == self.Database[i][1] and y == self.Database[i][2].

If you aren't after the keys, please clarify your question.

Upvotes: 2

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