Topic 1 Flashcards
Python counts from
0
CPU stands for… and is composed off …
It’s composed of 2 types of storage: …
Central processing unit
Control unit and arithmetic logic unit (ALU)
primary and secondary unit
3 coding components
Sequence of instructions
Control of flow
A way to stop
Algorithm
Step by step instructions on how to complete a task
Program
A set of instructions represented in the form of a programming language
int represents … and common uses are …
whole numbers (-2, 0, 2)
counting purposes
float represents … and common uses are …
real numbers (3.14)
numeric calculations
str represents … and common uses are …
sequence of characters (“hello”)
keys, input/output
bool represents … and common uses are …
true or false
control flow in programs
NoneType represents … and common uses are …
(None)
return type of a function that appears to not return anything
**
power
*
multiplication
/
division
+
addition
-
subtraction
%
modulus
Can ints and floats be mixed in arithmetics?
Yes, python will automatically convert int to float if needed
== vs =
== is an equality operator, compares 2 values, returns true if values are equal
= is an assignment operator, used to assign a value to a variable not compare
!=
not equal to
< / >
smaller / larger than
<= / >=
smaller than / larger than or equal to
== / != / < / > / <= / >= return … values
boolean (true / false)
boolean operators
and (returns true if all values are true), or (returns true if at least 1 value is true)
Any … of some type is evaluated to true when we use bool ()
print (bool (“Text”)) –>
print (bool (“”)) –>
print (bool (102)) –>
print (bool (0)) –>
non-empty or non-zero value
True
False
True
False
Strings are … objects
non-scalar
type function is …
a built in function that takes an object as input and returns what type it is (e.g. string)
print(“Apples” == “apples”) –>
print(“Apples” < “apples”) –>
print(“Apples” > “apples”) –>
False
True
False
ASCII converts letter to numbers and A lower than a
lexical order
the arrangement of a set of items with a recursive algorithm, such as the entries in a a dictionary whose order depends on their first letter unless these are the same in which case it is the second which decides, and so on
str has a length corresponding to …
the number of characters in the sequence
the len() function …
Checks the length of the function
name = “Python”
print(name[0])
print(name[1])
print(name[2])
print(name[3])
print(name[4])
print(name[5])
print(“Value of name is: “, name)
print(“Memory ID of name is: “, id(name))
name = “C++”
print(“Value of name is: “, name)
print(“Memory ID of name is: “, id(name))
P
y
t
h
o
n
Value of name is: Python
Memory ID of name is: 140487979014320
Value of name is: C++ (reassigment)
Memory ID of name is: 140487979638192
Are primitive data types (such as a string) mutable or immutable?
immutable
An object is considered mutable if … and immutable if …
its state or value can be modified after it is created
its value cannot be changed after it has been created
Trying to change Hello to Hallo (e to a)
str1 = “Hello”
str1[1] = ”a”
Would return … because
TypeError: ‘str’ object does not support item assignment
because string is immutable
Would need to reassign string from Hello to Hallo
Strings can”t be broken in parts
Define helper function
Define helper function
from pytest import approx
def error_message(actual, expected):
return f’Actual {actual} != Expected {expected}’
primitive data types
you bind them to a variable
int, float, bool, None, string
what function accesses the memory address of an object
id()
what function converts memory address to hex code
hex()
what operator compares whether 2 variables point to the same memory id
is
f you want to access the value of more than one index, you can use
[index_start : index_end] where index_start and index_end are integers
Note that this will give you the values starting from index_start and until index_end - 1
what function sorts strings by their lexical order
sorted()
