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01-introduction.md

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+---
+title: Python Basics Recap
+teaching: 0
+exercises: 0
+---
+
+::::::::::::::::::::::::::::::::::::::: objectives
+
+- Understanding key concepts in Python
+
+::::::::::::::::::::::::::::::::::::::::::::::::::
+
+:::::::::::::::::::::::::::::::::::::::: questions
+
+- Python Refresher
+
+::::::::::::::::::::::::::::::::::::::::::::::::::
+
+This course follows on from the python introduction course. To ensure that we are starting from similar positions, there follows a short multiple choice quiz on key python concepts that we will be building on through this course.
+
+## Variables and Lists
+
+::::::::::::::::::::::::::::::::::::: challenge
+
+### 1\. Assigning a value to a variable
+
+We wish to store the string `Cat` as a value in the variable `animal`, which of these lines of code will do this for us?
+
+1. `animal = 'Cat'`
+2. `animal = Cat`
+3. `Cat = animal`
+4. `animal(Cat)`
+
+:::::::::::::::  solution
+
+Answer 1 is correct
+
+:::::::::::::::::::::::::
+
+:::::::::::::::::::::::::::::::::::::::::::::::
+
+::::::::::::::::::::::::::::::::::::: challenge
+
+### 2\. Assigning values to a list
+
+We wish to create a list of values, which of these lines of code is valid to do this?
+
+1. `varlist = [34, 57, '2d']`
+2. `varlist = (12, 'vr', 95)`
+3. `varlist = 'xcf', 12, 97`
+
+:::::::::::::::  solution
+
+Answer 1 is correct
+
+:::::::::::::::::::::::::
+
+:::::::::::::::::::::::::::::::::::::::::::::::
+
+::::::::::::::::::::::::::::::::::::: challenge
+
+### 3a. Indexing characters in a string
+
+Lists and strings both contain multiple indexed values (in the case of strings these are specifically individual characters rather than other values). If we have a variable `animal` which contains the string `penguin`, which of these options will print the first character (`p`) for us?
+
+1. `print(animal[0])`
+2. `print(animal[1])`
+3. `print(animal['p'])`
+
+:::::::::::::::  solution
+
+Answer 1 is correct
+
+:::::::::::::::::::::::::
+
+:::::::::::::::::::::::::::::::::::::::::::::::
+
+::::::::::::::::::::::::::::::::::::: challenge
+
+### 3b. Indexing characters in a string (slicing)
+
+We can also select whole sections of lists and strings, not just single elements. Using the same variable `animal`, containing the string `penguin`, as above, which of these options will print the last 2 characters for us? (Note that there is more an one correct answer)
+
+1. `print(animal[5:])`
+2. `print(animal[6:])`
+3. `print(animal[6:7])`
+4. `print(animal[5:7])`
+5. `print(animal[-2:])`
+6. `print(animal[:-2])`
+
+:::::::::::::::  solution
+
+Answers 1, 4, and 5 are correct
+
+:::::::::::::::::::::::::
+
+:::::::::::::::::::::::::::::::::::::::::::::::
+
+## Loops
+
+::::::::::::::::::::::::::::::::::::: challenge
+
+### 4\. Constructing a `for` loop
+
+Please write a simple `for` loop which will print out each of the characters in the `animal` variable one at a time.
+
+:::::::::::::::  solution
+
+```python
+for char in animal:
+    print(char)
+```
+
+:::::::::::::::::::::::::
+
+:::::::::::::::::::::::::::::::::::::::::::::::
+
+## Software Modules
+
+::::::::::::::::::::::::::::::::::::: challenge
+
+### 5\. Loading new functions
+
+We want to use the functions in the `numpy` library in our code. How do we open this library in our code?
+
+1. `import numpy`
+2. `load numpy`
+3. `open numpy`
+
+:::::::::::::::  solution
+
+Answer 1 is correct
+
+:::::::::::::::::::::::::
+
+:::::::::::::::::::::::::::::::::::::::::::::::
+
+## If statements and conditionals
+
+::::::::::::::::::::::::::::::::::::: challenge
+
+### 6\. Conditionals
+
+Which of these conditional tests returns a `True` result?
+
+1. `4 > 3`
+2. `'a' != 'b'`
+3. `6 >= 6.0`
+4. `'3' == 3`
+5. `3 > 'c'`
+
+:::::::::::::::  solution
+
+Answers 1, 2, and 3 return `True` results. 4 returns `False`. 5 raises an Error.
+
+:::::::::::::::::::::::::
+
+:::::::::::::::::::::::::::::::::::::::::::::::
+
+::::::::::::::::::::::::::::::::::::: challenge
+
+### 7\. If statements
+
+What is printed when this `if` statement is used?
+
+```python
+if 4 > 5:
+    print('A')
+elif 4 <= 5:
+    print('B')
+elif 4 < 5:
+    print('C')
+else:
+    print('D')
+```
+
+1. `A`
+2. `B`
+3. `C`
+4. `B` and `C`
+5. `D`
+6. `A` and `D`
+
+:::::::::::::::  solution
+
+`B`. Both `4 <= 5` and `4 < 5` would return a `True` result, but the `if` statement is exited as soon as the `True` result is returned.
+
+:::::::::::::::::::::::::
+
+:::::::::::::::::::::::::::::::::::::::::::::::
+
+
+:::::::::::::::::::::::::::::::::::::::: keypoints
+
+- variables
+- lists
+- indexing
+- loops
+- conditionals
+
+::::::::::::::::::::::::::::::::::::::::::::::::::
+
+