Variables and Expressions Flashcards
What is a variable?
a named item, such as x or num_people, that holds a value.
What is incrementation?
A statement that causes a variable’s value to increase.
What is an identifier?
The name of a variable.
What are the rules for identifers?
Cannot start with a number. Cannot contain special characters other than underscore. Cannot be a reserved word.
What is an object?
Any item in Python.
What is name binding?
The process of associating names with interpreter objects.
What is garbage collection?
The process of deleting unnecessary objects.
What are the properties of objects?
Value, Type and Identity.
What is id()?
A function that returns the memory address an object is stored at.
What is type()?
A function that returns the type of an object
Are strings mutable?
No.
Are integers mutable?
No.
What is Overflow?
An error that occurs when a value is too large to be stored in the memory allocated by the interpreter.
What are the minimum and maximum floating point values?
Min: 2.3 x 10^-308, Max: 1.8 x 10^308
How do you manipulate significant figures in Python?
Use print(f’{}’). Put variable:.xf inside the curly brackets with x indicating the desired decimal place.
What is an expression?
A combination of items that evaluates to a value.
What is the order of precedence?
Parentheses, exponent, unary - (negative), multiplication = division = modulo, addition = subtraction, left-to-right.
What are compound operators?
A method of incrementing a variable. Syntax is an arithmetic operator in front of an equals sign.
What is floor division?
A form of division that rounds the quotient down to the nearest whole number.
What is modulo?
A form of division that returns the remainder.
How does Python distinguish between modules and scritps?
Scripts have the line “if __name__ == ‘__main__’”.
How do you access objects from a model after it’s imported?
By using dot notation. module.variable.
What is a function?
A list of statements that can be executed by referring to the function’s name.
What is an argument?
An item that is passed to a function.
What is randrange(x)?
A function that returns a random number from 0 to x -1.
What is randint(x)?
A function that returns a random number from 0 to x.
What is random.seed()?
A function that determines the initial value that all random functions draw from. By default, random functions draw from the system clock.
What is Unicode?
A list of numbers that each represent one character.
What is a code point in Unicode?
The term for the numbers in Unicode.
What are Escape sequences?
A method of modifying a string from inside the string. They start with a backslash.
What is a raw string.
A kind of string that ignores escape sequences. The syntax is r’text’.
What is ord()?
A function that returns the encode integer value of a one character string.
