Python Essentials Edube Study Set
lexis
(a dictionary) a set of words the language offers its users each program has its dictionary
Basic Operators
+ - * / // % **
print(-6//4) print(6.//-4)
-2 -2.0
print(-4 + 4) print(-4. + 8)
0 4.0
What happens if python runs into an invocation like this function_name(argument)
1) checks if the name is legal 2) checks functions requirements for number of arguments allows you to invoke the function in this way 3) leaves the code and jumps into the function you want to invoke 4) executes the code 5) returns to your code andresumes execution
What is the decimal value of the following binary? 1011
11
How to write eleven million one hundred eleven thousand one hundred and eleven in python
11111111 or 11_111_111
example of literal
123 one hundred twenty three
break down 14 % 4
14 // 4 = 3 3 * 4 = 12 14 - 12 = 2
print(0.0000000000000000000001)
1e-22
print(14 % 4)
2
print(6 // 3) print(6 // 3.) print(6. // 3.)
2 2.0 2.0
print("2") print(2)
2- string 2- integer
print(0x123)
291
print(12 % 4.5)
3.0
scientific notation
300000000 = 3 x 10 ^8 in python 3E10 exponent has to be integer base may be integer
print(2+2)
4
print(2 ** 3) print(2 ** 3.) print(2. ** 3) print(2. ** 3.)
8 8.0 8.0 8.0
print(0o123)
83
Who created python?
Guido van Rossum
print("Hello World!")
Hello World!
print("Hello, Python!")
Hello, Python!
python is an example of
High-level programming language
IDLE
Integrated Development and Learning Environment
What is the best definition of a script?
It's a text file that contains instructions which make up a Python program
What is CPython
It's the default, reference implementation of Python, written in the C language
How did python get its name?
Monty Python
how to not divide
NO: division by zero int division by zero find remainder of a division by zero
None literal
NoneType used to represent absence of a value
print("Programming","Essentials","in", sep="***", end="...") print("Python")
Programming***Essentials***in...Python
Select the true statements (two) Python is a good choice for creating and executing tests for applications Python is a good choice for low-level programming Python is free, open-source, and multiplatform Python 3 is backwards compatible with Python 2
Python is a good choice for creating and executing tests for applications Python is free, open-source, and multiplatform
what is CPython?
The default implementation of the Python programming language
What is the expected behavior of the following code? print("Hello!")
The program will output Hello! on the screen
What is machine code
This is low-level programing language consisting of binary digits/bits that the computer can read and understand
print(True > False) print(True < False)
True False
boolean values
True = 1 False = 0
\n meaning
\ is the escape character n is newline
Boolean algebra
a part of algebra which makes use of only two distinct values: true and false, denoted as 1 and 0
source code
a program written in a high-level programming language
semantics
a set of rules determining if a certain phrase makes sense the program has to make sense
syntax
a set of rules used to determine if a certain string of words forms a valid sentence each language has its rules and they must be obeyed
What do you call a file containing a program written in a high level programming language
a source file
debugger
allows you to inspect code step by step
What are the four fundamental elements that make a language
alphabet, lexis, syntax, semantics
Integer division (//)
always gives int result unless one or more float
integer division round
always rounds to nearest int value always goes to lesser int also known as floor division
A complete set of known commands is called:
an instruction list
what do you call a computer program which directly executes instructions written in a program language
an interpreter
keywords
argument (End here) equal sign(=) value (" ")
What can a function do?
cause some effect evaluate a value return it as the function's result
type
characteristic of numeric value which determines its kind range and application
What do you call a command-line interpreter which lets you interact with your OS and execute Python commands and scripts
console
literals
data whose values are determined by the literal itself used to encode data and to put them in your code
end keyword
determines the characters the print() function sends to the output once it reaches the end of its positional arguments. continus at end of sentence, no newline also seen as end="\n"
what is /
division always float
disadvantages of interpretation
don't expect interpretation to ramp up your code to high speed, your code will share the computer's power with the interpreter, so it can't be really fast; both you and the end user have to have the interpreter to run your code.
python goals
easy and intuitive open source understandable suitable for everyday tasks
quote inside string
either escape character 'I\'m happy' open and close string using opposite set of symbols "I'm happy" 'He said "Python" not "typhoon"'
advantages of compilation
execution of translated code is faster only the user has to have the compiler, the end user may use the code without it the translated code is stored using machine language
What is **
exponentiation left is base right is exponent
source file
file containing the source code
What is print?
function name
which is int and which is float 4 4.0
int = 4 float = 4.0
What is python? Compiler or Interpreter?
interpreter
What is true about compilation (two)
it tends to be faster than interpretation The code is converted directly into machine code executable by the processor
what is *
multiplication int rule
what is a string?
must be surrounded by quotes will be taken as data
putting \ in string
must double it or it is an escape \\
Literals
notations for representing some fixed values in code
floating-point (floats)
numbers that contain fractions or decimals
floats
numbers with decimals
Types of literals and examples
numeric 123 string "I am a literal"
integers (int)
numerical numbers without fractions positive or negative
what does print() do?
outputs an empty line
What do functions demand the presence of?
parentheses
octal
preceded by 0o taken from [0..7] range only
hexadecimal
preceded by 0x
want parentheses to appear
print("I like \"Monty Python\"") or print('I like "Monty Python"')
"I'm" ""learning"" """Python""" With newline
print("\"I'm\"\n\"\"learning\"\"\n\"\"\"Python\"\"\"")
"I'm" ""learning"" """Python""" broken up
print(' "I','m" ', sep="'") print(' ""learning"" ') print(' """Python""" ')
python file extension
py
Where can functions come from?
python itself(built-in) python add-ons(modules) write them yourself
Jython
python written in java
What is %
remainder left at int division
Integer rule when both ** are int when at least one ** is float
results in int results in float
sep keyword
separated the outputted arguments with whatever follows sep=""
alphabet
set of symbols used to build words of a certain language must be in recognizable script
What type of literals are the examples? "1.5", 2.0, 528, False
string float int boolean
What type of literals are the examples? "Hello ", "007"
strings
What arguments does print() expect
strings numbers characters logical values objects etc
binary system
system of numbers with 2 as the base made up of 1 and 0 ex 1010 = 10
what is the effect the print() function causes?
takes its arguments converts then into human readable form if needed--not strings sents resulting data to output device
disadvantages of compilation
the compilation itself may be a very time-consuming process, you may not be able to run your code immediately after making an amendment you have to have as many compilers as hardware platforms you want your code to be run on.
what is the expected behavior of the following program? prin("Goodbye!")
the program will generate an error message on the screen
compilation
the source program is translated once (however, this act must be repeated each time you modify the source code) now you can distribute the file worldwide; the program that performs this translation is called a compiler or translator;
console
where you launch newly written code
integers
whole numbers (positive and negative)
editor
will support in writing the code
advantages of interpretation
you can run the code as soon as you complete it, there are no additional phases of translation; the code is stored using programming language, not machine language, this means that it can be run on computers using different machine languages; you don't compile your code separately for each different architecture.
interpretation
you can translate the source program each time it has to run called an interpreter as it has to interpret the code every time it is intended to be executed