PYTHON DICTIONARIES

PYTHON DICTIONARIES
The dictionaries are like a little in-memory database, Dictionaries are Python’s most powerful data collection. It lets us do fast database-like operations on Python. Dictionaries have different names for different languages

• PHP - Associative arrays

• Java - property or hash map

• Property bag - C#

So the idea of the dictionary is putting more than one thing in it and has ways of indexing it. We index the thing we put in the dictionary with a look-up tag. Dictionaries are enclosed in curly braces {} and consist of one or more key-value pairs separated by colons. For example

my_dict = {
"name": "John",
"age": 30,
"City": "New York"
}

In this dictionary, name, age, and city are keys while John, 30, and New York are their values respectively.
You can also make an empty dictionary using empty curly braces

my_dict = {}
print (my_dict)
{}

You can change the values, for example:

my_dict["age"] = 31

One use of dictionaries is counting how often we see something. You can use dictionaries to count the frequency of elements in a list or string. For example

counts = dict()
print (‘Enter a line of text: ‘)
line = input (‘ ’)
words = line.split()
print (‘words:’, words)
For word in words :
count [word] = counts.get(word, 0) + 1
print (‘count’, counts)

Also when working with API, dictionaries are often used to display JSON responses.
A list is a collection that is in an organized order while a dictionary is a lot of values each with its own label.