# Programming Cheat Sheet by godley

### Data types

 name value string "­any­thi­ng1­234­!@£­\$%" integer 1234 float 1.2345 bool True/False

### Variable naming rules

 1. Easy to remember 2. Short 3. No spaces 4. Cannot start with a number 5. Can only contain letters, numbers and unders­cores

### Collec­tions and generics

 Name Usage Code List Multiple items in one variable ["ap­ple­", "­ban­ana­", "­str­awb­err­y"] Dictionary Multiple key-value pairs in one variable {"he­llo­": "­wor­ld"}

### Casting

 cast what it does str() converts to a string int() converts to an integer float() converts to a float
Casting is used to convert between values. It needs to occur before doing any mathem­atical calcul­ations with an input() from a user because user input is always strings.

### Variable assignment

 ```name = "abcdef123" age = 18 height = 3.14```

### Useful python functions

 print(­"­tex­t") outputs text to screen input(­"­tex­t") prints text and allows input from a user round(­3.14) rounds a float down to an integer

### Compar­ators

 symbol mean­ing == equal to > larger than < less than >= larger than or equal <= less than or equal != not equal

### Boolean operators

 and both values must be true or either value may be true xor either value may be true, but not both

### Arithmetic operators

 + add - subtract * multiply / divide ** power % modulus

### Condit­ionals

 ```value = 3 if value < 4:         print("less than 4") elif value > 2:         print("larger than 2") else:         print("some other value")```
else and elif must follow an if. Else cannot come before elif. Whitespace before the print statements indicates they are only to print if the condition is met

### Loops

 ```# infinite loop while True:         print("cheese!") # counter loop - 0-9 for i in range(10):         print(i) # iterating a list collection = ['apple', 'orange', 'banana'] for value in collection:         print(value)```

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