Opstap

Deze pagina bevat uitvoerbare code. Activeren

Canonieke uitwerking van de opstap. Pak 6_opstap.zip uit naast het notebook; de bestanden staan dan in assets/.

Opdracht 1

Een regel uit een tekstbestand bevat de newline nog. repr maakt dat teken zichtbaar.

with open("../problems/assets/woorden.txt") as file:
    for line in file:
        print(repr(line))

with open("../problems/assets/woorden.txt") as file: for line in file: print(repr(line))

'appel\n'
'peer\n'
'banaan\n'
'kiwi\n'
'mango\n'

Opdracht 2

Tel de regels.

count = 0
with open("../problems/assets/woorden.txt") as file:
    for _ in file:
        count = count + 1
print(count)
assert count == 5

count = 0 with open("../problems/assets/woorden.txt") as file: for _ in file: count = count + 1 print(count) assert count == 5

5

Opdracht 3

print krijgt de newline van de regel al mee; gebruik end="" om geen tweede newline toe te voegen.

with open("../problems/assets/woorden.txt") as file:
    for line in file:
        print(line, end="")

with open("../problems/assets/woorden.txt") as file: for line in file: print(line, end="")

appel
peer
banaan
kiwi
mango

Opdracht 4

Zet elke regel om naar een getal en tel de getallen op.

total = 0
with open("../problems/assets/metingen.txt") as file:
    for line in file:
        total = total + int(line)
print(total)
assert total == 1393

total = 0 with open("../problems/assets/metingen.txt") as file: for line in file: total = total + int(line) print(total) assert total == 1393

1393

Opdracht 5

Bewaar het grootste getal dat je tot nu toe hebt gezien.

highest = 0
with open("../problems/assets/metingen.txt") as file:
    for line in file:
        measurement = int(line)
        if measurement > highest:
            highest = measurement
print(highest)
assert highest == 226

highest = 0 with open("../problems/assets/metingen.txt") as file: for line in file: measurement = int(line) if measurement > highest: highest = measurement print(highest) assert highest == 226

226

Opdracht 6

Schrijf tien regels en lees het bestand daarna terug.

with open("telling.txt", "w") as file:
    for number in range(1, 11):
        print(number, file=file)
telling = ""
with open("telling.txt") as file:
    for line in file:
        telling = telling + line
print(telling, end="")
assert telling == "1\n2\n3\n4\n5\n6\n7\n8\n9\n10\n"

with open("telling.txt", "w") as file: for number in range(1, 11): print(number, file=file) telling = "" with open("telling.txt") as file: for line in file: telling = telling + line print(telling, end="") assert telling == "1\n2\n3\n4\n5\n6\n7\n8\n9\n10\n"

1
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10

Opdracht 7

Lees het ene bestand en schrijf geselecteerde regels naar het andere.

def strip_newline(line):
    """Geeft de regel terug zonder het regeleinde aan het eind."""
    if len(line) > 0 and line[-1] == "\n":
        return line[:-1]

    return line


with open("../problems/assets/woorden.txt") as source:
    with open("lang.txt", "w") as target:
        for line in source:
            if len(strip_newline(line)) > 4:
                print(line, end="", file=target)
long_words = ""
with open("lang.txt") as file:
    for line in file:
        long_words = long_words + line
print(long_words, end="")
assert long_words == "appel\nbanaan\nmango\n"

def strip_newline(line): """Geeft de regel terug zonder het regeleinde aan het eind.""" if len(line) > 0 and line[-1] == "\n": return line[:-1] return line with open("../problems/assets/woorden.txt") as source: with open("lang.txt", "w") as target: for line in source: if len(strip_newline(line)) > 4: print(line, end="", file=target) long_words = "" with open("lang.txt") as file: for line in file: long_words = long_words + line print(long_words, end="") assert long_words == "appel\nbanaan\nmango\n"

appel
banaan
mango