Answers for "dict() python"

python dictionary

#Creating dictionaries
dict1 = {'color': 'blue', 'shape': 'square', 'volume':40}
dict2 = {'color': 'red', 'edges': 4, 'perimeter':15}

#Creating new pairs and updating old ones
dict1['area'] = 25 #{'color': 'blue', 'shape': 'square', 'volume': 40, 'area': 25}
dict2['perimeter'] = 20 #{'color': 'red', 'edges': 4, 'perimeter': 20}

#Accessing values through keys
print(dict1['shape'])

#You can also use get, which doesn't cause an exception when the key is not found
dict1.get('false_key') #returns None
dict1.get('false_key', "key not found") #returns the custom message that you wrote 

#Deleting pairs
dict1.pop('volume')

#Merging two dictionaries
dict1.update(dict2) #if a key exists in both, it takes the value of the second dict
dict1 #{'color': 'red', 'shape': 'square', 'area': 25, 'edges': 4, 'perimeter': 20}

#Getting only the values, keys or both (can be used in loops)
dict1.values() #dict_values(['red', 'square', 25, 4, 20])
dict1.keys() #dict_keys(['color', 'shape', 'area', 'edges', 'perimeter'])
dict1.items() 
#dict_items([('color', 'red'), ('shape', 'square'), ('area', 25), ('edges', 4), ('perimeter', 20)])

haskey python

d = {'a': 1}
d.has_key('a')

python dict

# decleration
my_dict = {
  'spam': 'eggs',
  'foo': 4,
  100: 'bar',
  2: 0.5
}

# access single values from the dictionary
print(my_dict['spam']) # eggs
print(my_dict['foo']) # 4
print(my_dict[100]) # bar
print(my_dict[2]) # 0.5

# iterate over the dictionary
for key, value in my_dict.items():
  print(key, value)

# get length of the dictionary
print(len(my_dict)) # 4

# modify the dictionary
my_dict['baz'] = 'qux' # adds a pair
my_dict['baz'] = 'quxx' # also updates it
del my_dict['spam'] # removes a pair

# other methods
print(my_dict.copy()) # Returns a copy of the dictionary
print(my_dict.fromkeys('added', 100)) # Returns a dictionary with the specified keys and their values
print(my_dict.get('foo')) # Returns the value of the specified key
print(my_dict.items()) # Returns a list containing a tuple for each key value pair
print(my_dict.keys()) # Returns a list containing the dictionaries keys
print(my_dict.values()) # Returns a list of all the values in the dictionary
my_dict.setdefault('a', 'b') # Returns the value of the specified key. If the key does not exist: insert the key, with the specified value
my_dict.pop('foo') # Removes the element with the specified key
my_dict.popitem() # Removes the last inserted key-value pair
my_dict.update({'baz': 'val'}) # Updates the dictionary with the specified key-value pairs
my_dict.clear() # Removes all the elements from the dictionary

python 3.7 insert at place in dict

# Insert dictionary item into a dictionary at specified position: 
def insert_item(dic, item={}, pos=None):
    """
    Insert a key, value pair into an ordered dictionary.
    Insert before the specified position.
    """
    from collections import OrderedDict
    d = OrderedDict()
    # abort early if not a dictionary:
    if not item or not isinstance(item, dict):
        print('Aborting. Argument item must be a dictionary.')
        return dic
    # insert anywhere if argument pos not given: 
    if not pos:
        dic.update(item)
        return dic
    for item_k, item_v in item.items():
        for k, v in dic.items():
            # insert key at stated position:
            if k == pos:
                d[item_k] = item_v
            d[k] = v
    return d

d = {'A':'letter A', 'C': 'letter C'}
insert_item(['A', 'C'], item={'B'})
## Aborting. Argument item must be a dictionary.

insert_item(d, item={'B': 'letter B'})
## {'A': 'letter A', 'C': 'letter C', 'B': 'letter B'}

insert_item(d, pos='C', item={'B': 'letter B'})
# OrderedDict([('A', 'letter A'), ('B', 'letter B'), ('C', 'letter C')])

dicts python

thisdict =	{
  "brand": "Ford",
  "model": "Mustang",
  "year": 1964
}
x = thisdict["model"]
print(x)
---------------------------------------------------------------------------
Mustang

dictionary in python

# Dictionaries in Python

ages = {"John": 43, "Bob": 24, "Ruth": 76} # Marked by { at beginning and a } at end

# ^^^ Has sets of keys and values, like the 'John' and 43 set. These two values must be seperated by a colon

# ^^^ Sets of values seperated by commas.