This question already has answers here:
How Python dict stores key, value when collision occurs? [duplicate]
(2 answers)
How are Python's Built In Dictionaries Implemented?
(3 answers)
Why can a Python dict have multiple keys with the same hash?
(5 answers)
Closed 4 years ago.
my_dict = {}
my_dict["qwerty"] = "some_value"
my_dict[114378642] = "some_other_value"
The above code contains a python dictionary containing two keys, where the first key is of type string and the second key is of type integer. Though both keys are of different types it produces the same hash i.e,
hash("qwerty") = 114378642
hash(114378642) = 114378642
and hence,
hash("qwerty") == hash(114378642) #True
Couldn't get a proper answer until now,
Firstly, I was under an impression that "only two similar objects
produce the same hash".
Secondly, how a python dictionary performs collision recovery in
the above case?
Finally, what is the initial capacity and of a python dictionary
in the first line of code?
hash() produces the same result as the int value you input, no surprise here.
>>> for i in range(10) : print i, hash(i)
...
0 0
1 1
2 2
3 3
4 4
5 5
6 6
7 7
8 8
9 9
Dictionaries use a different hashing to store their values.
Related
This question already has answers here:
How do I merge two dictionaries in a single expression in Python?
(43 answers)
Closed 2 years ago.
I have:
a = {'name':'alfred','class':'2'}
b = {'year':'1990','town':'NY'}
And I want to merge a and b to get:
{'name':'alfred','class':'2', 'year':'1990','town':'NY'}
So far I created a new dict and iterate through both to set key values pairs.
Python3.9
c = a | b
Python3.5+
c = {**a, **b}
This question already has answers here:
Accessing elements of Python dictionary by index
(11 answers)
Closed 3 years ago.
I created a dictionary with key with multiple values. How can I access those values from single key?
d = {'a':(1,2,3),('b','c'):5}
I want to access the values 1,2 or 3 using the key 'a'.
d['a'] is a tuple, and like any tuple you can access it's elements as such: d['a'][0] which holds the value 1
This question already has answers here:
Multiple assignment and evaluation order in Python
(11 answers)
Swap 2 values of 2 variables without using a third variable; python
(5 answers)
Is there a standardized method to swap two variables in Python?
(8 answers)
Closed 5 years ago.
Why does
a = 3
b = 5
a,b = a + b,a
print a,b
-------
8 3
differ from
a = 3
b = 5
a = a + b
b = a
print a,b
------
8 8
Can someone explain how Python interprets the assignments differently? Does Python still keep the old value of a in the first paragraph of code, when a is assigned to a + b? (a= a+b)
Also, does these assignment properties change from Python 2 to Python 3?
This question already has answers here:
Python's `range` function with 3 parameters
(3 answers)
Closed 5 years ago.
I am trying to create a list of lists using a list comprehension method. I found this solution online:
output = [1,2,3,4,5,6]
[output[i:i+2] for i in range(0, len(output), 2)]
This is the first time I have come across a 3rd argument in range, What does the 3rd argument of range do?
The 3rd argument of range is the stepping, meaning how much to increment the last value for:
>>> for i in range (0,10,2):
... print i
0
2
4
6
8
This question already has answers here:
Create a list with initial capacity in Python
(11 answers)
Closed 9 years ago.
I want to do the following :
l = list()
l[2] = 'two'
As expected, that does not work. It returns an out of range exception.
Is there any way to, let say, define a list with a length ?
Try this one
values = [None]*1000
In place of 1000 use your desired number.