Checklist For Python Beginners | by Liu Zuo Lin | in Python in Plain English

I’ve come across a couple of students who can do machine learning stuff, but cannot write a proper nested for loop to do a simple task (which isn’t very ideal).

This checklist thus aims to be a benchmark for the stuff a Python beginner needs to be decently familiar/competent with before I feel he/she is ready to move on to harder stuff eg. OOP, DSA, web dev or whatever. Of course, this is my personal opinion (formed from tutoring Python) and it could differ from yours.

1) Basic Python Syntax

Using the print() function
Using the print() function with commas eg. print(1, 2, 3)
Comments in Python using #
The Assignment Operator =
What makes a variable name valid?
How to ask the user for input using the input() function
What happens when x=4 and then x=5?
How to switch the values of 2 variables

2) Basic Data Types

Integers int
Floats float
Strings str
Booleans bool
Type casting eg. how to convert an integer to string and vice versa

3) Numerical Operators

Addition +
Subtraction -
Multiplication *
True division /
Floor division // + how is this different from true division?
Modulus %
Exponentiation **
Order of operations — which ones of these are executed first? (PEDMAS)
Addition for strings (also known as concatenation)
Multiplication for strings
Numerical operators with incompatible types (using type casting)
Compound assignment operators eg. +=, -=, *= and so on

4) Conditional Statements

Comparison operators ==, !=, <, <=, >, >=
If-elif-else loop syntax + which statements execute given a condition
Logical operators and, or & not
De Morgan's Law — not (X and Y) equals not X or not Y

5) Functions

Built-in functions eg. print(), input(), range(), abs()
Syntax of defining your own function — 0, 1, 2 … arguments
How to call your own function
How to call a function in another function

6) For Loops

Basic for loop syntax
The range function with 1 argument
The range function with 2 arguments
The range function with 3 arguments
The range function with 3 arguments + step is negative
The break keyword and what it does

7) While Loops

Basic while loop syntax
How to save your computer from an infinite while loop
How to NOT create an infinite while loop
The break keyword and what it does
When to use for loop VS when to use while loop
Looping condition vs breaking condition

8) Strings

Basic string syntax — how to create a string
String addition and multiplication
Indexes in strings, and how to index strings to get single characters
Basic string slicing with start and end
String slicing with empty start and end arguments
String slicing with negative start and end arguments
String slicing with 3 arguments start, end and step
String slicing with 3 arguments + empty arguments
String slicing with 3 arguments + negative step
Common string functions — len, upper, lower, strip, count, index, find, rfind, replace, isupper, islower, isalpha, isnumeric, isalnum
Checking if a string contains a character or substring using in
Whitespace and escape characters eg. " ", "n", "t" etc
Formatted strings eg. f"My name is {name}"
How to iterate through strings using for loop or while loop
Strings + compound assignment operators += and *=

9) Lists

Basic list syntax — defining a list
List addition and multiplication
Indexes in lists + how to index lists
List slicing (this works the same way as strings)
Adding new elements to back of list using .append
Replacing existing elements in list
More common list methods eg. len, index, count etc
Checking if an element exists inside list using in
Iterating through a list using a for loop vs while loop

10) Dictionaries

Basic dictionary syntax — defining a dictionary
What data types are valid dictionary keys/values?
Accessing values in a dictionary using a key
Adding new key-value pairs into existing dictionary
Replacing existing key-value pair in dictionary
Updating dictionary value using compound assignment operators
Common dictionary methods — len, values, items, keys
Checking if key/value exists inside dictionary
Iterating through dictionaries

11) Tuples

Basic tuple syntax — defining tuples
Tuples vs lists — concept of immutability
Simple tuple unpacking
Tuple indexing & slicing (same as lists)

12) Sets

Basic set syntax — defining sets
What values we can or cannot add into a set
Why we use sets
Adding new values into a set using .add
Removing values from sets using .remove
Common set methods — len, intersection, union

13) File Reading & Writing

Simple file reading using with open(filename) as f
Read, append and overwrite modes
Simple file writing using with open(filename, mode) as f

14) Accumulation Using A Loop

Getting 15 from [1, 2, 3, 4, 5] — sum of numbers in list
Getting 120 from [1, 2, 3, 4, 5] — products of numbers in list
Getting 9 from [1, 2, 3, 4, 5] — sum of odd numbers in list
Getting "ieae" from "pineapple" — keeping only vowels
Getting [1, 4, 9, 16, 25] from [1, 2, 3, 4, 5]
Getting {1:1, 2:4, 3:9, 4:16} from [1, 2, 3, 4, 5]

15) Nested Loops

Being able to do the following using nested loops (no hardcoding)
Print the following pattern given n. For instance, if n=3 and n=5:

1 12 123 1 12 123 1234 12345

Print the following pattern given n. For instance, if n=3 and n=5:

1 21 321 1 21 321 4321 54321

Print the following pattern given n. For instance, if n=3 and n=5:

321 21 1 54321 4321 321 21 1

Print the following pattern given n. For instance, if n=3 and n=5:

321 32 3 54321 5432 543 54 5

Print the following pattern given n. For instance, if n=3 and n=5:

  1  12 123     1    12   123  1234 12345

Print the following pattern given n. For instance, if n=3 and n=5:

  1  21 321     1    21   321  4321 54321

Conclusion

Did you manage to check 95% of the boxes?

Some Final words

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