The grammar, structure, or order of the elements in a language statement.
Back
Three types of steps in a script/program
Front
Sequential - one after another
Repeated - step done multiple times
Conditional - performs one of several different steps based on a condition
Back
Symantic error
Front
Python statements are written correctly, but script and/or program does not perform the task intended
Back
Program
Front
Script or set of instructions that tell CPU what to do
Stored instructions for CPU to follow
Back
Script
Front
Enter a sequence of statements (lines) into a file using a text editor
Tell python to execute
Back
Guardian pattern
Front
Guard against division by 0 error by using and
>>> x = 6
>>> y = 0
>>> x >= 2 and y != 0 and (x/y) > 2
False
-- the y!=0 statement guards against division by zero
Back
Output devices
Front
Means by which CPU provides information back to user
Monitor, printer, speakers
Back
In Python 2, integer division
Front
Truncates (drops resulting fraction of division)
3/2 = 1 (the 0.5 gets dropped)
Back
Compound statement
Front
A statement that consists of a header and a body.
The header ends with a colon (:).
The body is indented relative to the header.
if / else -- if / elif / else -- try / except
Back
Secondary memory
Front
Where information is stored
Slower than main memory
Memory is retained after shut down or reboot
Hard drive, jump stick, cd
Back
Two way decisions (if / else)
Front
if x<10:
print 'x is less than 10'
else:
print 'x is equal to or greater than 10'
Back
Branch
Front
One of the alternative sequences of statements in a conditional statement
Back
Constants
Front
Numbers, letters or strings that do not change
Back
Multi-way decisions (if / elif / else)
Front
x=int(15)
if x <10:
print "x is less than 10"
elif x>10 and <50:
print "x is greater than 10 but less than 50"
else:
print "x is greater than 50"
Back
Variable names
Front
Must begin with a letter or an underscore "_"
Can contain no spaces
Cannot be a Python keyword
Back
Nested conditional
Front
A conditional statement that appears in one of the branches of another conditional statement
Back
Concatenation
Front
Joining together (of strings)
X='Jerry '
Y='is old'
Print X + Y
>>> Jerry is old
Back
try and except
Front
When you know a sequence of instructions may encounter a problem
Statements to be added if an error occurs
---------------------------------------------------------------
astr=raw_input('Enter a number: ')
try:
istr=int(astr) #convert to integer?
except:
istr=Non-numerical input received
print istr
Back
Traceback
Front
A list of the functions that are executing, printed when an exception occurs
Back
Syntax error
Front
Mistake made in grammar while writing Python statement
Back
Interactive
Front
Method of using Python, typing code in one line at a time (at the Python prompt >>>)
Back
Logic error
Front
Error in the way python statement was written
Usually related to the order of the words or characters used in the statement
Back
Guardian pattern
Front
Where we construct a logical expression with additional comparisons to take advantage of the short-circuit behavior.
Left to right evaluation of statement involving logical operators (and / or / not)
Back
RAM
Front
Random Access Memory
Main memory - were info is store that CPU needs very quickly
Fast, small, temporary storage
Lost on shutdown or reboot
Back
Comments
Front
Everything to the right of # on a specific line is ignored by python compiler and is considered a comment
Multi line comments can be entered with
'''
Comment line 1
Comment line 2
'''
Back
Operator precedence rules
Front
Parenthesis
Exponentation
Multiplication, division, remainder
Addition and subtraction
Flow from left to right
Back
if
Front
If x<10:
Print 'Less than 10'
If x >=10:
Print 'Equal to or greater than 10'
Back
Short circuit
Front
When Python is part-way through evaluating a logical expression and stops evaluation because the final value for the expression is known without needing to evaluate the rest of the expression.
Left to right evaluation of statement involving logical operators (and / or / not)
Back
Input devices
Front
Means by which to receive input from user
Keyboard, mouse, microphone
Back
CPU
Front
Central processing unit
Executes instructions
Runs the program very fast
Back
Python file extension
Front
***.py
Back
Assignment statement
Front
Assigns a value to a chosen variable
Back
Boolean expression
Front
Expression that is either true or false
Back
type
Front
e = hello
>>>type (e) Must put the variable in ( )
<type 'str'> type of e is a string
Back
Many elifs are permitted
Front
x=45
if x<=5:
print "x is less than or equal to 5"
elif x<=10:
print "x is greater than 5 but = to or less than 10"
elif x<=25:
print "x is greater than 10 but = to or less than 25"
elif x>25:
print "x is greater than 25"
Back
Comparison operators
Front
Less than ( < ) x < y
Less than or equal ( <= ) x <= y
Greater than ( > ) x > y
Greater than or equal ( >= ) x >= y
Equality ( == ) x == y
Inequality ( != ) x != y
Back
Chained conditional
Front
A conditional statement with a series of alternative
branches