reading-notes

Class 06

How to Random Module

• Provides access to functions that support many operations
• Generates random numbers
• Randint - accepts two parameters(lowest_number, highest_number)

import random
print random.randint(0, 5)

• can multiple for larger numbers

• Choice - generate a random value from a sequence

  random.choice( ['First Choice', 'Second Choice', 'Third Choice'])
  

• Shuffle - shuffles elements in the list in place so they are in a random order

from random import shuffle
x = [[element_in_list]] for element_in_list in range(10)]
shuffle(x)

• randrange- Generates a randomly selected element from range(start, stop, step)

  import random
  for i in range(3):
    print random.randrange(0, 101, 5)
  

• chooses two outcomes ``` import random import itertools

outcomes = { ‘heads’:0, ‘tails’:0, } sides = outcomes.keys()

for i in range(10000): outcomes[ random.choice(sides) ] += 1

print ‘Heads:’, outcomes[‘heads’] print ‘Tails:’, outcomes[‘tails’] ```

What is Risk Analysis

• Risk - probability of unwanted incident
• process of identifying risks in apps or software that you built and prioritizing them to test.
• find the risk areas before they become a problem, the earlier the better.
• Unavoidable risks
  • time allocated for testing
  • defect leakage due to complexity of size of app
  • Urgency to deliver
  • Incomplete requirements
• Three levels of risk
  • High
  • Medium
  • Low
• Risk ID
  • Business
  • Testing
  • Premature Release
  • Software
• Risk Assessment
  • Effect
  • Cause
  • Likeliehood
• Three steps to perform Risk Analysis
  • Searching the risk
  • Analyzing the impace of each individual risk
  • Measure for risk indentified

Big O Notation

• Algorithm Efficiency
• Transfering Data over the internet changes based on the amount of data being transferred.
• O(1) constant time with respect to the sizes of input, doesnt take longer with more input
• O(N) Scales linearaly with the amount of input, twice as much data takes twice as much time.
  • N is the size of the List
• Different steps in algorithm, add them together
• Drop constants
• Different inputs use different variables
• Drop non-dominant terms

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