int("24")
24
520//60
8
520%60
40
d = {} # create empty dictionary
# add 'a':5
d['a'] = 5
print(d)
d['a'] = 7
print(d)
print(d['a'])
# how to check if a key is in a dictionary
'b' in d
{'a': 5}
{'a': 7}
7
False
s = "this is a long sentence"
d = {}
d2 = {'a':20, 'b':46} # create a non-empty dictionary
# Approach 1; go through each letter in s
for c in "abcdefghijklmnopqrstuvwxyz":
d[c] = 0
for c in s:
if c in d:
d[c] = d[c] + 1 # d[c] += 1
else:
d[c] = 1
print(d)
# Approach 2; go through each letter in the alphabet
for c in "abcdefghijklmnopqrstuvwxyz":
n = s.count(c)
d[c] = n
print(d)
{'a': 1, 'b': 0, 'c': 1, 'd': 0, 'e': 3, 'f': 0, 'g': 1, 'h': 1, 'i': 2, 'j': 0, 'k': 0, 'l': 1, 'm': 0, 'n': 3, 'o': 1, 'p': 0, 'q': 0, 'r': 0, 's': 3, 't': 2, 'u': 0, 'v': 0, 'w': 0, 'x': 0, 'y': 0, 'z': 0, ' ': 4}
{'a': 1, 'b': 0, 'c': 1, 'd': 0, 'e': 3, 'f': 0, 'g': 1, 'h': 1, 'i': 2, 'j': 0, 'k': 0, 'l': 1, 'm': 0, 'n': 3, 'o': 1, 'p': 0, 'q': 0, 'r': 0, 's': 3, 't': 2, 'u': 0, 'v': 0, 'w': 0, 'x': 0, 'y': 0, 'z': 0, ' ': 4}
s = "this is a long sentence"
s.count('e')
3
# create new and empty set
s = set()
# create a new and non-empty set
t = {1,2,3}
print(s)
print(t)
s.add(10)
s.add(20)
s.add(30)
print(s)
s.remove(20)
print(s)
xs = list(s)
print(xs)
set()
{1, 2, 3}
{10, 20, 30}
{10, 30}
[10, 30]
d = {"John": 123, "Kelly":334, "Jon":100, "Alice":900}
xs = list(d)
print(xs)
ks = d.keys()
vs = d.values()
items = d.items()
print(ks)
print(vs)
print(items)
# ACCUMULATOR PATTERN
sum = 0 # accumulator variable
for key in d.keys():
sum = sum + d[key]
print(sum)
['John', 'Kelly', 'Jon', 'Alice']
dict_keys(['John', 'Kelly', 'Jon', 'Alice'])
dict_values([123, 334, 100, 900])
dict_items([('John', 123), ('Kelly', 334), ('Jon', 100), ('Alice', 900)])
1457
xs = [10,20,30,40]
product = 1 # accumulator variable
for val in xs:
product = product * val
print(product)
# produce a string of consonants in s
s = "this is a sentence"
result = ""
for c in s:
if c not in 'aeiou ':
result = result + c
print(result)
thsssntnc
# produce a list of even numbers from a list of numbers
nums = [10,23,76,84,99]
result = []
for num in nums:
if num%2 == 0:
result.append(num)
print(result)
[10, 76, 84]
xs = [("John",123), ("Kelly",334), ("Jon",100), ("Alice",900)]
d = {}
for (a,b) in xs:
d[a] = b
print(d)
{'John': 123, 'Kelly': 334, 'Jon': 100, 'Alice': 900}
def extract_digits(num):
result = []
while True:
if num == 0:
break
digit = num%10
num = num//10
result.insert(0,digit)
#result.append(digit)
#result.reverse()
return result
def no_repeats1(num):
digits = extract_digits(num)
unique_digits = set()
for digit in digits:
if digit not in unique_digits:
unique_digits.add(digit)
else:
return False
return True
def no_repeats2(num):
digits = extract_digits(num)
return len(digits) == len(set(digits))
no_repeats1(5784658)
False
no_repeats2(5468)
True
extract_digits(5784658)
[5, 7, 8, 4, 6, 5, 8]
57846%10
6
57846//10
5784
xs = [1,2,3]
xs.reverse()
print(xs)
[3, 2, 1]
set([1,2,3,1,2])
{1, 2, 3}
xs = [1,2,3,1,2]
len(xs) == len(set(xs))
def main():
guess_num = 1
target = produce_target()
while True:
user_guess = input("Enter guess number",guess_num, ": ")
# do error check
guess_num = guess_num + 1
nbulls = numberOfBulls(target,user_guess)
ncows = numberOfCows(target,user_guess)
print("Bulls = ",nbulls,"Cows = ",ncows)
if guess_num == 11:
print("You lost")
break
if nbulls == 4:
print("You won")
break
main()
xs = [1,2,3]
y = xs.reverse()
print(y)
None
class Student():
#constructor
def __init__(self,n,m,cs):
self.name = n
self.major = m
self.courses = cs
s1 = Student("John","CSC",[])