Python list slicing
Step by step explanation of a "reverse a list" trick from previous post

Perhaps the most interesting operation you can do with lists is called slicing.
IT gives you opportunity to get portion of your list.
For example:

🔹 Step 1: Getting list slice
x = ['a','b','c','d','e']
print(x[0]) #first element - a
print(x[0:1]) #first element, but we have explicitly set both start and end - ['a']
print(x[0:2]) #first two elements - ['a', 'b']

🔹 Step 2: Starting from the end
WE can also go through list from end to beginning, in this case, we use negative indexes:

print(x[-3:-1]) # This will return the slice starting from the 3rd element from the end (c) and stopping before the 1st element from the end (e).

Output: ['c', 'd']

🔹 Step 3: Introducing increment
We can also ad increment to slicing. In all previous examples increment was one, but what if we want to get every second element of the list?

print(x[0:5:2]) # starting from first element, ending with last one, with increment of 2

Output: ['a', 'c', 'e']

🔹 Step 4: Omitting slicing parameters
As you can see, full slicing formula would be:

my_list[start_index:end_index:increment]

But we can omit (leave out/exclude) any of those 3 parameters
For example:

print(x[:3]) # We omitted first parameter,  this will print first 3 elements of the list 
print(x[3:]) # this will print rest 2 elements  (from 4th to end)
print(x[:3:2]) # this will print first 3 elements with increment 2
print(x[:]) # no start and end index, this will print entire list!
print(x[::-1]) # this will also print entire list, but with negative increment, starting from last to first one -> REVERSED LIST

Output:
['a', 'b', 'c']
['d', 'e']
['a', 'c']
['a', 'b', 'c', 'd', 'e']
['e', 'd', 'c', 'b', 'a']

I put some effort into creating this so please let me know if you learned something valuable and if you like this type of content 😊.

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Python tricks and tips
Section 1: Lists
Lesson 2: Flatten a list

Code snippet to copy:
import itertools
a = [[1, 2], [3, 4], [5, 6]]
b = list(itertools.chain.from_iterable(a))
print(b)

Python Notes for Professionals book

📄 816 pages

🔗 Book link

#Python
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Python tricks and tips
Section 1: Lists
Lesson 3: Combining different lists

Code snippet to copy:
a=[‘a’,’b’,’c’,’d’]
b=[‘e’,’f’,’g’,’h’]
for x, y in zip(a, b):
print(x,y)

Python tricks and tips
Section 1: Lists
Lesson 4: Negative indexing lists

Code snippet to copy:
a = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
a[-3:-1]

Python tricks and tips
Section 1: Lists
Lesson 5: Analyzing the most frequent on the list

Code snippet to copy:
a = [1, 2, 3, 4, 2, 2, 3, 1, 4, 4, 4]
print(max(set(a), key = a.count))

Python tricks and tips
Section 2: Strings
Lesson 6: Splitting the string

Code snippet to copy:
a="Python is the language of the future"
b=a.split()
print(b)

Python tricks and tips
Section 2: Strings
Lesson 7: Reversing the string

Code snippet to copy:
a=”python”
print(“Reverse is”, a[::-1])

Introduction to Python Programming
Course Notes

📄 164 pages

🔗 Book link

#Python
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Python tricks and tips
Section 2: Strings
Lesson 8: Creating a single string

Code snippet to copy:
a = [“I”, “am”, “not”, “available”]
print(“ “.join(a))

Python tricks and tips
Section 2: Strings
Lesson 10: Checking if two words are anagrams

Code snippet to copy:
from collections import Counter
def is_anagram(str1, str2):
return Counter(str1) == Counter(str2)
print(is_anagram(‘taste’, ‘state))
print(is_anagram(‘beach’, ‘peach’))

Python Frameworks and Libraries

Django is the most popular framework among Python developers. No surprise here, seeing how Web development is so popular among Python users. Interestingly, 43% of respondents are using IPython, which clearly shows it’s being used not only for scientific purposes, but for general software development as well.

A large number of respondents also specified Flask as their framework of choice.

Hi folks,

For all you who have been here for a long time, you probably noticed that after certain period of inactivity, this channel started posting content again. First owner of this channel (a friend of mine, admin of AI India), didn't have enough time to take care of it so he transferred ownership to me. I am 27 year old software engineer, living in Europe, owner and founder of @bigdataspecialist channel (and many more, i will add them in comment if somebody is interested into checking them).

I started posting interactive content, with one of my employees helping me with it since i don't have too much free time. I really hope you like it 😉

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That's it, I really hope you like the new content, feel free to reach me out if you need anything and also write any suggestions what would you like to see in this or other channel of mine in comments. Thank you all and have a nice day.

Python tricks and tips
Section 3: Matrix
Lesson 11: Transposing a matrix

Code snippet to copy:
mat = [[8, 9, 10], [11, 12, 13]]
new_mat=zip(*mat)
for row in new_mat:
print(row)