Lab 5.sagews

# Topic 1: Filtering
# Assume X = ['i2', 'o4', '23', 'e5', '99', 'e7', 'o9', 'i1', 'e7']
# Please classify strings starting with 'i', 'o', and 'e' into three different list variables called ilist, olist, and elist. The rest will be classified into list variable called otherlist.

X_list = ['i2', 'o4', '23', 'e5', '99', 'e7', 'o9', 'i1', 'e7']
i_list = []
o_list = []
e_list = []

for x in X_list:
    if x[0] == 'i':
        i_list.append(x)
    elif x[0] == 'o':
        o_list.append(x)
    elif x[0] == 'e':
        e_list.append(x)

print ('i_list = %s' % i_list)
print ('o_list = %s' % o_list)
print ('e_list = %s' % e_list)

i_list = ['i2', 'i1'] o_list = ['o4', 'o9'] e_list = ['e5', 'e7', 'e7']

# Topic 2: List comprehension
# Fibonacci Sequence is defined as F(n) = F(n-1) + F(n-2); F(0) = F(1)=1.
# Use list comprehension to generate a list of Fibonacci Sequence containing F(0) to F(20).

# In mathematics, I will write it as [fab(n) : n = 0, 1, ..., 20].
# So, if direct convert to mathematics, it should looks like the following. BUt I not sure if this is the
# the list comprehension that you want.
#

def fab(n):
    if n==0 or n ==1:
        return 1
    else:
        return fab(n-1) + fab(n-2)

fab_list = [fab(n) for n in range(20)]
print ('fab_list = %s' % fab_list)

# Or ...(which look very weird)
f_list = [1, 1]

nothing = [f_list.append(f_list[-1] + f_list[-2]) for n in range(20-2)]
print f_list

fab_list = [1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181, 6765] [1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181, 6765]

# Topic 3: Function
# Write a function to return a list of the common elements between two lists without using set or dict in Python.
# These two input lists can have duplicate elements.

def find_common(a_list, b_list):
    common_list = []
    for a in a_list:
        if a in b_list:
            common_list.append(a)
    #
    return common_list

#
#  Test
#
a_list = [1,2, 3, 5]
b_list = [1,4, 2]
find_common(a_list, b_list)

[1, 2]

# Topic 4: Parsing
# As defined in Assignment #1, store the attributes of each gate description in gates.csv (attached) into a two-dimensional list called gates using the code below to read the file.
# f = open('gates.csv', 'r')
# for line in f:
#     // parse each line representing a gate

# Results should have removed all the white spaces in the lines and I can get a neat print out like below when I type print gates[2]
# ['2', 'not', 'B', '-', '-']

# Hints: you may need a type specific method called str.split() which can be found through google.

f = open('gates.csv', 'r')
token_list_list = []
for line in f:
    token_list = line.split(",")
    token_list = [token.strip() for token in token_list]
    if token_list[0] == 'name':
        continue

    token_list_list.append(token_list)
#
token_list_list = sorted(token_list_list)
gate = token_list_list
print (gate[2])

['2', 'not', 'B', '-', '-']

a = "hello  "
a.strip()
s = "4,    nor,      1,           0,            Q"
s_list = s.split(",")
# s_list
[s.strip() for s in s_list]

'hello' ['4', 'nor', '1', '0', 'Q']