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+# Casting (Changing the data type)
+
+## Strings & Integer Variables
+
+```python
+number1 = "5" # string variable 
+number2 = 10 # integer variable
+```
+
+Right now, we've got two (2) variables set:
+
+* Number1 (String) | Value = "5"
+
+* Number2 (Integer) | Value = 10
+
+### Error 1
+
+If I just added these 2 variables together:
+
+```py
+number3 = number1 + number2 # results in a syntax error
+```
+
+#### Fixing error 1
+
+```python
+number3 = int(number1) + number2
+```
+
+By adding "int(" to the variable, we change the data type of variable "number1" from a **string** into an **integer.**
+
+```python
+print(number3) # prints "15"
+```
+
+### Adding 2 strings together
+
+```python
+number3 = number1 + str(number2) # prints "510" as 10 is added to the right of the 5, like how you would add two characters/letters together, as both variables are now strings
+```
+
+### Error 2
+
+```python
+number1 = "ggg"
+number2 = 5
+number3 = number2 + number1
+```
+
+Even if I was to convert "number1" into a string, there would still be an error:
+
+```python
+number3 = int(number1) + number2
+```
+
+And this is because "ggg" is not a number, so it is an invalid value for any integer or float variable.
+
+However, we can add these two variables together:
+
+##### Fixing Error 2
+
+```python
+number3 = number1 + str(number2) # and this gives us "ggg5" // See "adding two strings together"
+```
+
+### Floats
+
+```python
+number1 = 11.55
+number2 = 3 # could be represented as a float or an integer, but to make sure it's an integer:
+
+number2 = int(number2)
+
+number3 = number1 + number2
+```
+
+```python
+number3 = float(number2) + number1
+```
+
+The same rules regarding converting strings/integers also apply to floats
+
+#### Types of errors
+
+* Syntax
+
+* Type
+
+### Other stuff
+
+* Changing a variable's data type to the current data type does not result in an error and the program continues to run
+
+## Full code
+
+```py
+number1 = "5"  # string variable 
+number2 = 10 # integer variable
+
+# number3 = number1 + number2 // Error 1
+
+number3 = int(number1) + number2 # Fixing Error 1
+print(number3)
+
+
+number1 = "ggg"
+number2 = 5
+
+#number3 = number1 + number2
+
+
+number3 = number1 + str(number2)
+print(number3)
+
+
+number1 = 11.55
+number2 = 3 # could be represented as a float or an integer, but to make sure it's an integer:
+
+number2 = int(number2)
+
+number3 = number1 + number2
+```
+
+## File Information
+
+* File Link: https://github.com/irisdroidology/python-learning/master/udemy/python-masterclass/11.casting.md
+
+* Discussion link: http://acord.software/stellarios/python-discussion
diff --git a/Udemy/Python Masterclass/12.strings.md b/Udemy/Python Masterclass/12.strings.md
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+# Strings
+
+These are both strings:
+
+```python
+"string"
+'string'
+```
+
+
+
+```python
+stringVar = "Hello" # string variable aka
+```
+
+## Printing parts of a string
+
+```python
+print(stringVar) # prints whole string
+print(stringVar[0]) # index value - starting from 0 // Prints "H"
+print(stringVar[1]) ## prints "e" 
+```
+
+* Indexing is how we can print parts of a string (as well as doing other things)
+
+* Index values start from 0 - the first value of a variable is the "0th" or where the index value is 0
+
+
+
+An error:
+
+```python
+print(stringVar[5]) # index error
+```
+
+* While there are 5 characters in the string "stringVar", if the index value is 5, then it is referring to the **6th** character, which doesn't exist, thus resulting in an index error:
+
+* ```
+  string index out of range
+  ```
+
+* 
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