Unit 2 - 2 Flashcards
What are variable assigned to?
An identifier and store a value in RAM
What is an identifier?
Must start with a letter and be a single word
Can variables be used to carry out calculations?
Yes
What does input ask for?
Computer will wait for a value from the user
What is casting?
Where variables and values can be converted to different data types
What is a string?
A variable that stores text rather than a number and is made up of a series of characters that can include spaces, symbols and numbers
What is concatenation?
Links things together, doing with the string using the ‘+’ operator
What is string traversal?
A software able to keep track of the position of every character within a string
How do you print the string length?
len(variable)
What is a ‘real’?
A decimal
What is ‘boolean’?
True or False
What is selection?
if variable == :
elif:
else:
What is a function?
from random import*
def identifier():
variable =
return variable
Define a procedure?
A block of code with an identifier which can be run anytime throughout a program
Give an example of a procedure?
def identifier():
What is an iteration loop, give an example?
variable =
count =
while count <=
variable = variable * count
print(variable)
count = count + 1
How do you break an iteration loop?
break
print(“end of loop”)
Iteration scenario - Output square numbers up to 144?
for x in range (1,13)
print(x**2)
What is an array?
A data structure that holds similar related data
What does an array store?
Similar, related data
What is the purpose of an array?
Reduces number of variables
What 2 things need to be declared to make an array?
Identifier + a size (number of elements it will hold)
What is the difference between 1D array and 2D array?
A 2D array can hold more than one set of data
How, using an array, would you find the name of the 3rd car in a set of data (SEE ONENOTE)?
third_car_name = cars[2]
REMEMBER ALWAYS STARTS AT 0
Why is data stored in a file?
So that it can be assessed again at a later date without losing any data what is being held
What are the 2 modes of file operation?
Read from
Write to
What are the 3 lines of close to open, read a line and then close a file?
file = openRead()
file = openWrite()
file.close()
Give an example of a text file?
file = open(‘names.txt’)
DONT FORGET EOF
What is a database?
A persistent store of related data, the data within is stored as records in files
What is an attribute?
One item of data
What do multiple related attributes create?
A record e.g. surname
What does the * represent?
Everything
Give an example of an SQL to retrieve data?
SELECT * FROM customers WHERE City = ‘London’
What is a subprogram?
A set of small programmes that are written within a larger program
What is the purpose of a subprogram?
Perform specific tasks
What are the 2 types of subprogram?
Procedures
Functions
Benefits of programming with subprograms?
Smaller in size - easier to write/test/debug
Can be saved separately as modules - saves time
Used repeatedly at various points - shorter programs code only written once
What happens when a procedure ends?
Mina program continues where it left off
What makes a function different to a procedure?
It manipulates data and returns result back to main program
