Chapters 2-4: Functions and Conditionals Flashcards

(36 cards)

1
Q

Boolean Expression

A

Expression either true or false.

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2
Q

=

A

Assignment operator

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3
Q

==

A

Comparison operator - equals

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4
Q

greater than, =/greater than, is/is not operators

A

> , >=, is, is not

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5
Q

elif

A

Used after the if, short for else if. can be as many as you want in a block, or none. Used same as if, ie if …..:

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6
Q

else

A

used at and of the block (if needed) - sets what happens if no conditions (if and elif) are met). used by itself, ie else:

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7
Q

nested conditional

A

when a conditional eg ‘else:’ has 2 sub braches, eg an if and an else

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8
Q

try/except

A

try: some code. if there is an error (eg cant float an input because it’s words), move on to the except:. No exception? skip the except:.

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9
Q

Guardian pattern

A

A logical expression guarding against a runtime error, using the fact logical expressions are evaluated left to right. eg [something] and x!=0 and (3/x)>2. x!=0 guards against runtime error caused if x=0, as 3 cant be divided by it.

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10
Q

what error message tells you about error locaction

A

tells you where python detected the error, not necessarily where it is. true error may be earlier in code.

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11
Q

Function

A

named sequence of statements that performs a computation, eg type()

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12
Q

Argument

A

the expression in the brackets of a function, ie the the expression the function “takes” before it “return”s a “value”

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13
Q

max()/min()

A

Functions which return the largest/smallest character/number in a string/comma’d list

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14
Q

len()

A

Function which returns the number of characters in a string

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15
Q

import math

A

Imports the “math” module. Can then be used, eg assign radians=0.7, height=math.sin(radians) (prefix functions with math.)

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16
Q

import random

A

Imports the “random” module, allows the generation of pseudorandom (deterministic but you cant really tell) with various random.functions

17
Q

x=random.random()

A

Assigns x as random number between 0.0 and 1.0 (inclusive of 0.0 but not 1.0)

18
Q

random.randint(1, 10)

A

Returns a pseudorandom number between 1 and 10 inclusive.

19
Q

x=[1, 3, 5, 7]

A

Assigns x as a sequence, from which individual numbers can be chosen.

20
Q

random.choice(x)

A

Returns a pseudorandom choice from a pre-assigned sequence, x.

21
Q

def

A

defines a function, eg def print_lyrics(): // [tab]print(‘xxxxx’). 1st line is head, ends with “:”. Rest is the body, indented.

22
Q

def x(y)
z(y)
z(y)

A

defines a function with (a) parameter(s). Python learns to do the same regardless of parameter if the y is the same in x(y) and z(y)

23
Q

fruitful vs void function

A

function which returns a ‘worked-out’ result eg input() or math.sqrt(), vs a function which performs a task eg print()

24
Q

return

A

used in the body of a function definition, to return the result of a fruitful function, eg def addtwo(a, b)//[tab]added=a+b//[tab]return added. Without final line, python adds the parameters but the result isnt reported, so it’s pointless.

25
None
A type of value, just like str or int, which means it is the result of a void function, or a fruitful function where the output has not been returned.
26
round(x, n)
Function, rouund a number, x, to n decimal places.
27
quit()
quit python/python environment
28
user_input=input('Type something!\n')
assigns user_input variable with the vavlue user enters
29
Semantic error
The situation in which a program executes but does not produce the results that were intended. No error message, just wrong result.
30
Syntactic error
Error on syntax, ie grammar, of the command which means the interpreter cannot intrpret it. Leads to error message.
31
Logic error
An error in logic, often due to order of statements being wrong, or how the relate to one another.
32
Variable
A name you can assign a value, e.g. a=45, message='hey man'. 'x' not needed for variables, but is for value. Python interprets these IDENTICALLY to their value unless changing the value with variable=something new. Case sensitive!
33
int()/float()/str()
returns argument as given type. convert with x=int('x') etc
34
**
exponentiation, eg 5**2 = 5^2 = 25. alongside
35
//
/ but truncates result to an interger, i.e. rounds down to nearest interger. 5.9//2=2.0
36
%
modulus, gives the remainder not the quotient. 7//3=2, 7%3=1. v. useful, used in clever ways.