Python : listes et données (sauf STD2A)

items = []
items.append("bread")
items.append("milk")
items.append("eggs")
print(len(items))
print(items)
print(items[1])
for item in items:
    print("-", item)
print("milk" in items)

3
['bread', 'milk', 'eggs']
milk
- bread
- milk
- eggs
True

grades = [12, 15, 9, 14]
total = 0
for g in grades:
    total = total + g
print(total / len(grades))
print(sum(grades) / len(grades))
print(max(grades), min(grades))
print(sorted(grades))
print(grades)

12.5
12.5
15 9
[9, 12, 14, 15]
[12, 15, 9, 14]

def position_of_largest(lst):
    best = 0
    for i in range(1, len(lst)):
        if lst[i] > lst[best]:
            best = i
    return best

def evens(lst):
    result = []
    for x in lst:
        if x % 2 == 0:
            result.append(x)
    return result

>>> position_of_largest([4, 9, 2, 9])
>>> position_of_largest([7])
>>> evens([3, 8, 5, 2, 6])
>>> evens([1, 3])

>>> position_of_largest([4, 9, 2, 9])
1
>>> position_of_largest([7])
0
>>> evens([3, 8, 5, 2, 6])
[8, 2, 6]
>>> evens([1, 3])
[]

a = [1, 2]
b = a
b.append(3)
print(a)
c = a[:]
c.append(4)
print(a)
print(c)

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

def find(lst, v):
    for i in range(len(lst)):
        if lst[i] == v:
            return i
    return -1

def has_duplicate(lst):
    for i in range(len(lst)):
        for j in range(i + 1, len(lst)):
            if lst[i] == lst[j]:
                return True
    return False

>>> find([5, 3, 8, 3], 3)
>>> find([5, 3, 8, 3], 7)
>>> find([], 1)
>>> has_duplicate([4, 1, 7, 1])
>>> has_duplicate([4, 1, 7])

>>> find([5, 3, 8, 3], 3)
1
>>> find([5, 3, 8, 3], 7)
-1
>>> find([], 1)
-1
>>> has_duplicate([4, 1, 7, 1])
True
>>> has_duplicate([4, 1, 7])
False

names = ["Ada", "Leo", "Zoe"]
scores = [15, 12, 17]
best = 0
for i in range(1, len(names)):
    if scores[i] > scores[best]:
        best = i
print(names[best], scores[best])
for i in range(len(names)):
    if scores[i] >= 15:
        print(names[i])

Zoe 17
Ada
Zoe

text = "les lettres les plus frequentes"
counts = [0] * 26
total = 0
for c in text:
    if c in "abcdefghijklmnopqrstuvwxyz":
        position = ord(c) - ord("a")
        counts[position] = counts[position] + 1
        total = total + 1
best = 0
for i in range(26):
    if counts[i] > counts[best]:
        best = i
print(chr(best + ord("a")), counts[best], total)

e 7 27

grid = [["X", "O", "X"], [" ", "X", "O"], ["O", " ", "X"]]
for row in grid:
    print(row[0] + "|" + row[1] + "|" + row[2])
count = 0
for r in range(3):
    for c in range(3):
        if grid[r][c] == "X":
            count = count + 1
print("X:", count)
print(grid[1][2])

X|O|X
 |X|O
O| |X
X: 4
O

def longest_word(sentence):
    words = sentence.split()
    best = words[0]
    for w in words:
        if len(w) > len(best):
            best = w
    return best

def word_count(sentence):
    return len(sentence.split())

>>> "a red fox".split()
>>> longest_word("the quick brown fox")
>>> word_count("the quick brown fox")
>>> "-".join(["a", "b", "c"])

>>> "a red fox".split()
['a', 'red', 'fox']
>>> longest_word("the quick brown fox")
'quick'
>>> word_count("the quick brown fox")
4
>>> "-".join(["a", "b", "c"])
'a-b-c'

u = [3 * n + 2 for n in range(5)]
print(u)

def f(x):
    return x * x - 4

xs = [-3, -1, 0, 2, 5]
ys = [f(x) for x in xs]
print(ys)
print([y for y in ys if y > 0])
print([n for n in range(1, 31) if n % 7 == 0])

[2, 5, 8, 11, 14]
[5, -3, -4, 0, 21]
[5, 21]
[7, 14, 21, 28]

ys = []
for x in xs:
    ys.append(f(x))

with open("notes.txt", "w") as f:
    f.write("ada 15\n")
    f.write("leo 12\n")

with open("notes.txt") as f:
    text = f.read()
print(len(text))

count = 0
with open("notes.txt") as f:
    for line in f:
        print(line.strip())
        count = count + 1
print(count, "lines")

14
ada 15
leo 12
2 lines

records = []
with open("rain.csv") as f:
    first = True
    for line in f:
        if first:
            first = False
        else:
            fields = line.strip().split(";")
            records.append([fields[0], int(fields[1]), int(fields[2])])
print(len(records), "records")
print(records[0])
total = 0
for r in records:
    if r[0] == "Brest":
        total = total + r[2]
print("Brest:", total, "mm")

9 records
['Brest', 1, 133]
Brest: 332 mm

wet = 0
for r in records:
    if r[0] != "Brest" and r[2] > 80:
        wet = wet + 1
print(wet)
winter = []
for r in records:
    if r[1] == 1 or r[1] == 2:
        winter.append(r[2])
print(sum(winter) / len(winter))
others = []
for r in records:
    if not r[0] == "Lyon":
        others.append(r[0])
print(len(others))

1
80.5
6

rows = [["girl", "bus"], ["boy", "bike"], ["girl", "walk"], ["girl", "bus"],
        ["boy", "bus"], ["boy", "walk"], ["girl", "bike"], ["boy", "bus"]]
genders = ["girl", "boy"]
modes = ["bus", "bike", "walk"]

table = []
for g in genders:
    table.append([0] * len(modes))

for row in rows:
    r = genders.index(row[0])
    c = modes.index(row[1])
    table[r][c] = table[r][c] + 1

print("      ", modes)
for r in range(len(genders)):
    print(genders[r], table[r], "total", sum(table[r]))

       ['bus', 'bike', 'walk']
girl [2, 1, 1] total 4
boy [2, 1, 1] total 4

id;class;mode
P01;A;bus
P02;A;bike
P03;B;walk
P04;A;bus
P05;B;bus
P06;B;walk
P07;A;walk
P08;B;bike
P09;A;bus
P10;B;walk

records = []
with open("trips.csv") as f:
    first = True
    for line in f:
        if first:
            first = False
        else:
            fields = line.strip().split(";")
            records.append([fields[1], fields[2]])

classes = ["A", "B"]
modes = ["bus", "bike", "walk"]
table = []
for c in classes:
    table.append([0] * len(modes))
for r in records:
    i = classes.index(r[0])
    j = modes.index(r[1])
    table[i][j] = table[i][j] + 1

for i in range(len(classes)):
    total = sum(table[i])
    print(classes[i], table[i], total, round(100 * table[i][0] / total), "% by bus")

A [3, 1, 1] 5 60 % by bus
B [1, 1, 3] 5 20 % by bus