Update README.md

Author: scxr

2020_07_14_course/README.md

@@ -18,6 +18,8 @@ Thank you for taking the time to read this write-up on the Python introductory c
     - [Functions](#functions)
       - [Lambdas](#lambdas)
 
+        
+
 ## Setting up Python
 
 Depending on your OS you will want to install the latest version of Python available from the official [Download Page](https://www.python.org/downloads/). The course will be using Python 3.8 or newer, and while most features work in previous versions it's best to be up-to-date with all the latest updates and security patches.
@@ -187,3 +189,80 @@ print(multiply(5, 2))
 ```
 
 Lambdas automatically return the value they're assigned to, so the `return` keyword can be omitted.
+
+### Loops and If statements
+
+#### While loops
+While loops work by running a certain piece of code while a given statement is true. So for example if you wanted to print all numbers up to 10 with a while statement, you would do this:
+```py
+i = 0
+while i<10:
+	print(i)
+	i += 1 # increment the counter
+```
+A trace table for this can be seen here:
+```markdown
+| Iteration | I  | While | Output    |
+|-----------|----|-------|-----------|
+| 1         | 0  | True  | 0         |
+| 2         | 1  | True  | 1         |
+| 3         | 2  | True  | 2         |
+| 4         | 3  | True  | 3         |
+| 5         | 4  | True  | 4         |
+| 6         | 5  | True  | 5         |
+| 7         | 6  | True  | 6         |
+| 8         | 7  | True  | 7         |
+| 9         | 8  | True  | 8         |
+| 10        | 9  | True  | 9         |
+| 11        | 10 | False | No output |
+```
+#### For loops
+For loops are similar to while loops however they work with ranges. These ranges can be different things, you can have ranges between numbers but similarly you can have ranges on strings. We will replicate the numbers between 1 and 10 with a for loop.
+```py
+for i in range(0,10):
+	print(i)
+```
+As you can see this is much more efficient, you do not need to increment the variable manually or even initialise it, the for loop does this itself. As stated above you can also do this on strings so i will show this below too:
+```py
+my_str = "hello world"
+for i in my_str:
+	print(i)
+"""
+Output:
+h
+e
+l
+l
+o
+
+w
+o
+r
+l
+d
+"""
+```
+As you can see it goes over each character individually, in an iterative process. 
+
+#### If / else/ elif statements
+If statements are a fundamental concept in the majority of programming languages and python is no different, this is used to check if a given condition is true. If it is then it will execute the code it is supplied if not it will go to through elif until one is true (if supplied) if none are true then it will go to the else statement. An example of this will be:
+```py
+age = int(input("Enter your age"))
+if age < 18:
+	print('You cannot enter the club')
+elif age > 18:
+	print('Welcome to the club')
+else:
+	print('Please provide ID, 18 year olds must be checked')
+
+"""
+>>> Enter your age
+>18
+Please provide ID, 18 year olds must be checked
+>>> Enter your age
+>16
+You cannot enter the club
+>>>Enter your age 
+>38
+Welcome to the club
+"""