Python is a versatile language that you can use for everything from web development to data science. And while it\’s easy to get started with Python, there are some advanced operations that you may have forgotten. In this blog post, we\’ll take a look at four advanced Python operations that you may have forgotten. From list comprehensions to generators, these techniques will help you get the most out of your Python code.
Pivot
There are many operations that can be performed on lists in Python, but there are a few that are often forgotten. One such operation is the pivot.
The pivot operation takes a list and rearranges it so that the first element is in the middle, the second element is at the beginning, and so on. This can be useful for creating new data structures or for performing certain algorithms.
To perform a pivot operation on a list, you must first select an index to use as the pivot point. This index can be any integer between 0 and the length of the list (exclusive). For example, if we have a list with five elements, we could choose to use an index of 2 or 3 as our pivot point.
Once the pivot point has been selected, the elements of the list will be rearranged so that all values before the pivot point are moved to after it, and vice versa. So, if our original list was [1,2,3,4,5] and we selected an index of 2 as our pivot point, our new list would be [3,4,5,1,2].
It\’s important to note that this operation is not destructive; that is, the original list is not modified. Instead, a new list is created with the desired order.
Melt
Melt is one of the most useful operations in pandas, especially when dealing with time series data. It allows you to unpivot a Data Frame from a wide format to a long format. This can be extremely helpful if you want to tidy up your data or make it easier to work with.
To melt a DataFrame, you simply specify which columns you want to keep (the id_vars), and which columns you want to unpivot (the value_vars). Let\’s take a look at an example:
We have a DataFrame with three columns: Date, Country, and Value. We can use the melt operation to unpivot this DataFrame into a long format like this:
Date Country Value
0 2019-01-01 00:00:00+00:00 USA 10.000000
1 2019-01-02 00:00:00+00:00 USA 11.111111
2 2019-01-03 00:00:00+00:00 USA 9.090909
Date Country Variable Value
0 2019-01-01 00:00:00+00:00 USA Value 10.000000
1 2019-01-02 00:00:00+00:60 USA Value 11.111111 2
2 2019-01-03 06;03;59
Stack
When we talk about stacks in Python, we are referring to a data structure that allows for efficient insertion and retrieval of data. Stacks follow a first-in, last-out (FILO) principle, which means that the first element added to the stack will be the last one to be removed.
There are a few different ways to create a stack in Python. The most common way is to use a list:
stack = []
We can then add elements to the stack using the append () method:
stack.append(\’a\’)
stack.append(\’b\’)
stack.append(\’c\’)
print(stack) # [\’a\’, \’b\’, \’c\’]
As you can see, the order of the elements in the stack is important. The last element added (c) is at the top of the stack and will be the first one removed.
We can remove elements from the stack using the pop() method:
print(stack.pop()) # c
print(stack.pop()) # b
print(stack) # [\’a\’]
As you can see, when we pop an element off the stack, it is removed from the top of the stack (last in, first out).
Unstack
There are a few advanced python operations that you may have forgotten. One such operation is unstacking. Unstacking is the process of taking a stack of items and removing the top item from the stack. This leaves the remainder of the stack in the same order.
To unstack an item, you must first have a stack of items. A stack is a Last In First Out (LIFO) data structure. That is, the last item added to the stack will be the first item removed from the stack. Python lists can be used as stacks. To add an item to a list, use the append() method. To remove an item from a list, use the pop() method. The pop() method removes and returns the last item in a list.
Here is an example of how to use the pop() method to unstack an item:
>>> my_list = [1, 2, 3]
>>> my_list.pop()
3
>>> my_list
[1, 2]
Conclusion
There are many Python operations that can be extremely useful but are often forgotten about. We hope this article has helped you remember some of the more advanced Python operations and that you can start using them in your own code. If you\’re ever stuck on a particular operation, don\’t hesitate to refer back to this article for a refresher. And if there\’s an operation you think we should have included, let us know in the comments below!