Lecture 8, Tue 10/30

- Average 86.54
- Medium: 89.75
- std: 11.91

'''
# Loops

# More on loops

name = "Bob"
for c in name:
    print(c)
    print("----")

print("resuming program execution")

# range function
    - range() is a function used for looping if we know
    the number of iterations we want to make.
    - range(x) returns a collection of numbers including
    0 up to (but not including) x
    - Think of range(4) as [0, 1, 2, 3]
'''
# Example using range()
for x in range(4):
    print("Hello!" * x)
    print("----")
'''
'''
# Example looping from numbers 2, 3, 4, 5 using range
for x in range(2,6):
    print(x)
    print("----")

# range is similar to substring - 1st parameter defines
# the 1st number and loops up to (but not including)
# the 2nd parameter's number
'''
'''
# Example using range with steps
for x in range(0, 10, 2):
    print(x)
    print("----")
'''
'''
# Example by manually updating a variable in the loop
intList = [2,4,8,16,32,64,128,256,1024]
counter = 1
for x in intList:
    print("2 ^ ", counter, "=", x)
    counter = counter + 1
'''


# Example: Write a function and run some assert tests

def hasOddNumber(list):
    ''' Returns True if the list has an odd number.
        Returns False otherwise
    '''
    for x in list:
        if (x % 2 != 0):
            return True
    return False

numbers1 = [2,4,5,6,8]
numbers2 = [0,10,20,30]
numbers3 = []

# Test by observation
print(hasOddNumber(numbers1))
print(hasOddNumber(numbers2))
print(hasOddNumber(numbers3))

# Test by assertions
assert hasOddNumber(numbers1) == True
assert hasOddNumber(numbers2) == False
assert hasOddNumber(numbers3) == False

- Accumulator Pattern

    - Useful for "accumulating" something while traversing
    a collection.
        Example: Count the number of times, count the
        number of characters in a string, ...

#Example

listOfStrings = ["this", "is", "a", "list", "of", "strings"]
numList = [8,2,6,4,0]

def computeLengthManually(someList):
    """ count the number of items in the list manually """
    elements = 0
    for e in someList:
        elements += 1 # elements = elements + 1
    return elements

print(computeLengthManually(listOfStrings))
print(computeLengthManually(numList))
'''
"""
# Another Example
sentence = '''
This is a pretty long sentence, with many many words and
letters, and a bad example of what good sentence structure
would look like, so don't do this
'''
print(sentence)

print(sentence.split())
# split() "splits" a string into a list of strings
# separated by ' ', '\n', or '\t' (whitespace)

print(sentence.split(','))
# split(',') "splits" the string into a list of strings
# separated by ','
# Notice that commas are removed from the actual values
# May be useful for comma separated value (csv) formats

# strip() string method
# Removes the whitespace at the beginning and end of
# strings
x = "     abc    "
print("---" + x + "---")
print("---" + x.strip() + "---") # removes whitespaces at ends

y = "--,!'fj,ka--"
print(y.strip("-,!'")) # removes these characters from
                       # the beginning and end
"""
"""
sentence = '''
This is a pretty long sentence, with many many words and
letters, and a bad example of what good sentence structure
would look like, so don't do this
'''

# Example
def countLongWords(someString):
    ''' counts words longer than 5 characters '''
    counter = 0
    words = someString.split()
    for w in words:
        if len(w) > 5:
            counter += 1
    return counter

print(countLongWords(sentence))
"""

''' Tuples
    - A tuple is similar to a list, but with small
    (but important) differences.
    - .sort() works for lists, but not tuples
    - inherently, tuples and lists are different,
    but logically they seem the same.
    - can change an element in a list, but can't
    change them in a tuple.
'''

'''
#Examples
oddNumbers = (1, 3, 5, 7)
print(oddNumbers)
print(type(oddNumbers))
print(oddNumbers[2]) #5

oddNumbers2 = [1, 3, 5, 7]
oddNumbers2[2] = 9
print(oddNumbers2)
# oddNumbers[2] = 9 ERROR, cannot change item in tuple
#print(oddNumbers)

oddNumbers = (1, 3, 9, 7)
print(oddNumbers)
'''
''' Namedtuples
    - Package heterogenous things into a multi-
    attribute item
    - We can represent more complex data into
    specific types
    - Ex: Students
        - Name, perm, major, DOB, address, GPA,
        full-time / part-time, international, ...
    - Creating multi-attribute things is the basis
    of object oriented programming.
'''
'''
#Example on using namedtuples

# Step 1: Allow your program to use namedtuples.
from collections import namedtuple

# Step 2: Design your object
Student = namedtuple("Student", "name perm major GPA")
# Parameters of function, 1st is name of the namedtuple
# type (Student).
# 2nd parameter is a string containing the names of
# attributes

# Step 3: Create objects
s1 = Student("John Doe", 1234567, "CS", 3.5)
s2 = Student("Jane Doe", 7654321, "MUSIC", 3.9)

print("Name of s1:", s1.name)
print("Perm of s1:", s1.perm)
print("GPA of s2:", s2.GPA)
print(s1)
print(s2)
print(type(s1))
'''