In [1]:

    

list1 = ['apple', 'banana', 'orange']
list1


    

    
Out[1]:





['apple', 'banana', 'orange']

In [2]:

    

list2 = [7, 11, 13, 17, 19]
list2


    

    
Out[2]:





[7, 11, 13, 17, 19]

In [3]:

    

list3 = ['text', 23, 66, -1, [0, 1]]
list3


    

    
Out[3]:





['text', 23, 66, -1, [0, 1]]

In [4]:

    

empty = []
empty


    

    
Out[4]:





[]

In [5]:

    

list1[0]


    

    
Out[5]:





'apple'

In [6]:

    

list1[-1]


    

    
Out[6]:





'orange'

In [7]:

    

list1[-2]


    

    
Out[7]:





'banana'

In [8]:

    

'orange' in list1


    

    
Out[8]:





True

In [9]:

    

'pineapple' in list1


    

    
Out[9]:





False

In [10]:

    

0 in list3


    

    
Out[10]:





False

In [11]:

    

0 in list3[-1]


    

    
Out[11]:





True

In [12]:

    

None in empty


    

    
Out[12]:





False

In [13]:

    

66 in list3


    

    
Out[13]:





True

In [14]:

    

len(list2)


    

    
Out[14]:





5

In [15]:

    

len(list3)


    

    
Out[15]:





5

In [16]:

    

del list2[2]
list2


    

    
Out[16]:





[7, 11, 17, 19]

In [17]:

    

new_list = list1 + list2
new_list


    

    
Out[17]:





['apple', 'banana', 'orange', 7, 11, 17, 19]

In [18]:

    

new_list * 2


    

    
Out[18]:





['apple',
 'banana',
 'orange',
 7,
 11,
 17,
 19,
 'apple',
 'banana',
 'orange',
 7,
 11,
 17,
 19]

In [19]:

    

[new_list] * 3


    

    
Out[19]:





[['apple', 'banana', 'orange', 7, 11, 17, 19],
 ['apple', 'banana', 'orange', 7, 11, 17, 19],
 ['apple', 'banana', 'orange', 7, 11, 17, 19]]

In [20]:

    

list2


    

    
Out[20]:





[7, 11, 17, 19]

In [21]:

    

list2.append(23)
list2


    

    
Out[21]:





[7, 11, 17, 19, 23]

In [22]:

    

#list.insert(index, obj)

list2.insert(0, 5)
list2


    

    
Out[22]:





[5, 7, 11, 17, 19, 23]

In [23]:

    

list2.insert(6, 29)
list2


    

    
Out[23]:





[5, 7, 11, 17, 19, 23, 29]

In [24]:

    

list2.insert(len(list2), 101)
list2


    

    
Out[24]:





[5, 7, 11, 17, 19, 23, 29, 101]

In [25]:

    

list2.insert(-1, 999) #it doesn't insert in the last position! :/
list2


    

    
Out[25]:





[5, 7, 11, 17, 19, 23, 29, 999, 101]

In [26]:

    

list2.remove(999) #remove the item 999
list2


    

    
Out[26]:





[5, 7, 11, 17, 19, 23, 29, 101]

In [27]:

    

list2.remove(list2[-1]) #here removed the last one!
list2


    

    
Out[27]:





[5, 7, 11, 17, 19, 23, 29]

In [28]:

    

l1 = [1, 2]
l2 = [3, 4]
l1.extend(l2)
l1


    

    
Out[28]:





[1, 2, 3, 4]

In [29]:

    

l2


    

    
Out[29]:





[3, 4]

In [30]:

    

list_unsorted = [10, 3, 7, 12, 1, 20]
list_unsorted.sort()
list_unsorted


    

    
Out[30]:





[1, 3, 7, 10, 12, 20]

In [151]:

    

list_unsorted.sort(reverse = True) # L.sort(key=None, reverse=False) -> None -- stable sort *IN PLACE*
list_unsorted


    

    
Out[151]:





[20, 12, 10, 7, 3, 1]

In [31]:

    

l1


    

    
Out[31]:





[1, 2, 3, 4]

In [32]:

    

l2


    

    
Out[32]:





[3, 4]

In [33]:

    

l2 = l1.copy()


    

In [34]:

    

l2


    

    
Out[34]:





[1, 2, 3, 4]

In [35]:

    

l2 == l1


    

    
Out[35]:





True

In [36]:

    

id(l1)


    

    
Out[36]:





139959401512328

In [37]:

    

id(l2)


    

    
Out[37]:





139959401231048

In [38]:

    

# It's better use copy()! Look: 

l1 = ['a', 'b', 'c']
l2 = l1
l1


    

    
Out[38]:





['a', 'b', 'c']

In [39]:

    

l2


    

    
Out[39]:





['a', 'b', 'c']

In [40]:

    

l2.append('d')
l2


    

    
Out[40]:





['a', 'b', 'c', 'd']

In [41]:

    

l1


    

    
Out[41]:





['a', 'b', 'c', 'd']

In [42]:

    

l1 == l2


    

    
Out[42]:





True

In [43]:

    

id(l1)


    

    
Out[43]:





139959401232840

In [44]:

    

id(l2) # same id! watch it.


    

    
Out[44]:





139959401232840

In [45]:

    

# Slicing

list10 = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
list10[4:] #took the 4th and goes on


    

    
Out[45]:





[4, 5, 6, 7, 8, 9, 10]

In [46]:

    

list10[4:6] #list[start:end] #item starts through end-1


    

    
Out[46]:





[4, 5]

In [47]:

    

list10[-2:] # the last 2 items in the array


    

    
Out[47]:





[9, 10]

In [48]:

    

list10[:-2] # everthing except the last 2 items


    

    
Out[48]:





[0, 1, 2, 3, 4, 5, 6, 7, 8]

In [49]:

    

# sliceable[start:stop:step]
list10[::2] # os pares (pula de 2 em 2)


    

    
Out[49]:





[0, 2, 4, 6, 8, 10]

In [50]:

    

list10[1::2] # os ímpares


    

    
Out[50]:





[1, 3, 5, 7, 9]

In [51]:

    

# and if I wanna know the index position of an item?

list10


    

    
Out[51]:





[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

In [52]:

    

list10.index(6)


    

    
Out[52]:





6

In [54]:

    

list20 = [1, 2, 1, 3, 1, 4, 1, 5]
list20.count(1) # it counts the number of times the "1" appears in the list


    

    
Out[54]:





4

In [55]:

    

list20.count(4)


    

    
Out[55]:





1

In [56]:

    

list20.count(10)


    

    
Out[56]:





0

In [57]:

    

list20.pop()


    

    
Out[57]:





5

In [58]:

    

list20


    

    
Out[58]:





[1, 2, 1, 3, 1, 4, 1]

In [59]:

    

list20.sort(reverse=True)


    

In [60]:

    

list20


    

    
Out[60]:





[4, 3, 2, 1, 1, 1, 1]

In [127]:

    

max(list20)


    

    
Out[127]:





4

In [128]:

    

sum(list20)


    

    
Out[128]:





13

In [129]:

    

courses = ['History', 'Math', 'Physics', 'CompSci']

for index, course in enumerate(courses):
    print(index, course)


    

    




0 History
1 Math
2 Physics
3 CompSci

In [130]:

    

course_str = ', '.join(courses)
print(course_str)


    

    




History, Math, Physics, CompSci

In [131]:

    

new_list = course_str.split(', ')
new_list


    

    
Out[131]:





['History', 'Math', 'Physics', 'CompSci']

In [137]:

    

cs_courses = ['History', 'Math', 'Physics', 'CompSci']
art_courses = ['History', 'Math', 'Art', 'Design']

list(set(cs_courses) & set(art_courses))


    

    
Out[137]:





{'History', 'Math'}

In [138]:

    

set(cs_courses).intersection(art_courses)


    

    
Out[138]:





{'History', 'Math'}

In [140]:

    

set(cs_courses).difference(art_courses) # there's only in cs_courses


    

    
Out[140]:





{'CompSci', 'Physics'}

In [142]:

    

set(art_courses).difference(cs_courses) #there's only in art_courses


    

    
Out[142]:





{'Art', 'Design'}

In [143]:

    

set(cs_courses).union(art_courses) # the two lists together


    

    
Out[143]:





{'Art', 'CompSci', 'Design', 'History', 'Math', 'Physics'}

In [147]:

    

x = ['Patton', 'Zorn', 'Hancock']

a, b, c = x
a


    

    
Out[147]:





'Patton'

In [148]:

    

b, c


    

    
Out[148]:





('Zorn', 'Hancock')

In [61]:

    

# Examples from https://docs.python.org/3/tutorial/datastructures.html

squares = []

for x in range(10):
    squares.append(x ** 2)

squares


    

    
Out[61]:





[0, 1, 4, 9, 16, 25, 36, 49, 64, 81]

In [62]:

    

squares2 = [x ** 2 for x in range(10)]


    

In [63]:

    

squares2


    

    
Out[63]:





[0, 1, 4, 9, 16, 25, 36, 49, 64, 81]

In [97]:

    

new_range = [i * i for i in range(5) if i % 2 == 0]
new_range


    

    
Out[97]:





[0, 4, 16]

In [64]:

    

combs = []

for x in [1, 2, 3]:
    for y in [3, 1, 5]:
        if x != y:
            combs.append((x, y))

combs


    

    
Out[64]:





[(1, 3), (1, 5), (2, 3), (2, 1), (2, 5), (3, 1), (3, 5)]

In [65]:

    

# and in list comprehension format:

combs2 = [(x, y) for x in [1, 2, 3] for y in [3, 1, 5] if x != y]
combs2


    

    
Out[65]:





[(1, 3), (1, 5), (2, 3), (2, 1), (2, 5), (3, 1), (3, 5)]

In [66]:

    

combs == combs2


    

    
Out[66]:





True

In [67]:

    

vec = [-4, -2, 0, 2, 4]
[x*2 for x in vec]


    

    
Out[67]:





[-8, -4, 0, 4, 8]

In [68]:

    

# exclude negative numbers:

[x for x in vec if x >= 0]


    

    
Out[68]:





[0, 2, 4]

In [69]:

    

# absolute in all numbers:

[abs(x) for x in vec]


    

    
Out[69]:





[4, 2, 0, 2, 4]

In [70]:

    

freshfruit = ['   banana                ', 'passion fruit      ']
[weapon.strip() for weapon in freshfruit] # strip() removes the white spaces at the start and end, including spaces, tabs, newlines and carriage returns


    

    
Out[70]:





['banana', 'passion fruit']

In [71]:

    

# list of 2-tuples like (number, square)

[(y, y**2) for y in range(6)]


    

    
Out[71]:





[(0, 0), (1, 1), (2, 4), (3, 9), (4, 16), (5, 25)]

In [72]:

    

# flatten a list using listcomp with two 'for'

vec = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
[num for elem in vec for num in elem]


    

    
Out[72]:





[1, 2, 3, 4, 5, 6, 7, 8, 9]

In [73]:

    

# in another words:

vec = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]

new_list = []

for elem in vec:
    for num in elem:
        new_list.append(num)

new_list


    

    
Out[73]:





[1, 2, 3, 4, 5, 6, 7, 8, 9]

In [74]:

    

from math import pi
[str(round(pi, i)) for i in range(1, 6)]


    

    
Out[74]:





['3.1', '3.14', '3.142', '3.1416', '3.14159']

In [75]:

    

# https://en.wikipedia.org/wiki/List_comprehension
s = {v for v in 'ABCDABCD' if v not in 'CB'}
print(s)


    

    




{'A', 'D'}

In [76]:

    

s


    

    
Out[76]:





{'A', 'D'}

In [77]:

    

type(s)


    

    
Out[77]:





set

In [87]:

    

s = {key: val for key, val in enumerate('ABCD') if val not in 'CB'}
s


    

    
Out[87]:





{0: 'A', 3: 'D'}

In [89]:

    

# regular list comprehension
a = [(x, y) for x in range(1, 6) for y in range(3, 6)]
a


    

    
Out[89]:





[(1, 3),
 (1, 4),
 (1, 5),
 (2, 3),
 (2, 4),
 (2, 5),
 (3, 3),
 (3, 4),
 (3, 5),
 (4, 3),
 (4, 4),
 (4, 5),
 (5, 3),
 (5, 4),
 (5, 5)]

In [91]:

    

# in another words:

b = []

for x in range(1, 6):
    for y in range(3, 6):
        b.append((x,y))
b


    

    
Out[91]:





[(1, 3),
 (1, 4),
 (1, 5),
 (2, 3),
 (2, 4),
 (2, 5),
 (3, 3),
 (3, 4),
 (3, 5),
 (4, 3),
 (4, 4),
 (4, 5),
 (5, 3),
 (5, 4),
 (5, 5)]

In [92]:

    

a == b


    

    
Out[92]:





True

In [95]:

    

# parallel/zipped list comprehension
c = [x for x in zip(range(1, 6), range(3, 6))]
c


    

    
Out[95]:





[(1, 3), (2, 4), (3, 5)]

In [100]:

    

# http://www.pythonforbeginners.com/basics/list-comprehensions-in-python
listOfWords = ['this', 'is', 'a', 'list', 'of', 'words']

[word[0] for word in listOfWords]


    

    
Out[100]:





['t', 'i', 'a', 'l', 'o', 'w']

In [103]:

    

# or...

listOfWords = ["this","is","a","list","of","words"]

items = [word[0] for word in listOfWords]

items


    

    
Out[103]:





['t', 'i', 'a', 'l', 'o', 'w']

In [104]:

    

[x.lower() for x in ['A', 'B', 'C']]


    

    
Out[104]:





['a', 'b', 'c']

In [105]:

    

[x.upper() for x in ['a', 'b', 'c']]


    

    
Out[105]:





['A', 'B', 'C']

In [106]:

    

string = 'Hello 12345 World'

numbers = [x for x in string if x.isdigit()]

numbers


    

    
Out[106]:





['1', '2', '3', '4', '5']

In [107]:

    

another_string = 'Hello 12345 World'

just_text = [x for x in another_string if x.isalpha()]

just_text


    

    
Out[107]:





['H', 'e', 'l', 'l', 'o', 'W', 'o', 'r', 'l', 'd']

In [108]:

    

just_text = [just_text[:5], just_text[5:]]
just_text


    

    
Out[108]:





[['H', 'e', 'l', 'l', 'o'], ['W', 'o', 'r', 'l', 'd']]

In [123]:

    

part1 = ''.join(just_text[0])
part1


    

    
Out[123]:





'Hello'

In [124]:

    

part2 = ''.join(just_text[1])
part2


    

    
Out[124]:





'World'

In [126]:

    

# finally...

just_text = [part1, part2]
just_text


    

    
Out[126]:





['Hello', 'World']

In [ ]: