Standardbiblioteket

from datetime import datetime, timedelta, timezone

# Ubevisst tidspunkt
lecture_time_unaware = datetime(2024, 3, 22, 12, 15, 00)
print(f'{str(lecture_time_unaware) = }')

# Konvertere fra ubevisst datetime til bevisst datetime, med bruk av
# den lokale tidssonen som var gjeldende den aktuelle datoen.
lecture_time_local = lecture_time_unaware.astimezone()
print(f'{str(lecture_time_local) = }')

# Noen tidssoner
tz_utc = timezone.utc # Universal Coordinated Time
tz_cet = timezone(timedelta(hours=1), name='CET') # Central European Time
tz_est = timezone(timedelta(hours=-5), name='EST') # Eastern Standard Time
tz_edt = timezone(timedelta(hours=-4), name='EDT') # Eastern Daylight Time
tz_pst = timezone(timedelta(hours=-8), name='PST') # Pacific Standard Time

# Konvertere til en annen tidssone kan gjøres på to måter:
#
#  new_datetime = old_datetime.replace(tzinfo=new_timezone)
#       endrer tidssonen uten å endre klokkeslettet/dato. For eksempel hvis
#       klokkeslettet var 12:15 i CET, vil det nye tidspunktet være 12:15 i
#       UTC.
# 
#  new_datetime = old_datetime.astimezone(new_timezone)
#       endrer tidssonen og klokkeslett/dato slik at det nye klokkeslettet
#      tilsvarer samme punkt i tid, bare oppgitt i en annen tidssone. For
#      eksempel hvis klokkeslettet var 12:15 i CET, vil det nye tidspunktet
#      være 10:15 i UTC.

lecture_time_replace_est = lecture_time_local.replace(tzinfo=tz_est)
print(f'{str(lecture_time_replace_est) = }')

lecture_time_astimezone_est = lecture_time_local.astimezone(tz_est)
print(f'{str(lecture_time_astimezone_est) = }')

# Dersom old_datetime er ubevvisst, vil både replace og astimezone fungere
# som replace, og vil da endre tidssonen uten å røre klokkeslett og dato.

import csv
# Du kan kopiere funksjonene for å lese/skrive csv-filer og bruke dem 
# som du ønsker uten å sitere.

def read_csv_file(path, encoding="utf-8", **kwargs):
    r''' Reads a csv file from the provided path, and returns its
    content as a 2D list. The default encoding is utf-8, the default
    column delimitier is comma and the default quote character is the
    double quote character ("), though this can be overridden with
    named parameters "delimiter" and "quotechar".'''
    with open(path, "rt", encoding=encoding, newline='') as f:
        return list(csv.reader(f, **kwargs))

def write_csv_file(path, table_content, encoding='utf-8', **kwargs):
    r""" Given a file path and a 2D list representing the content, this
    method will create a csv file with the contents formatted as csv.
    By defualt the delimiter is a comma and the quote character is
    the double quote, but this can be overridden with named parameters
     "delimiter" and "quotechar". """
    with open(path, "wt", encoding=encoding, newline='') as f:
        writer = csv.writer(f, **kwargs)
        for row in table_content:
            writer.writerow(row)

# Eksempeler på bruk. Først, en 2D-liste med innholdet i tabellen.
org_content = [
    ["Name", "Age"],
    ["Ola", 74],
    ['"Kari"', "73"],
]
print("Original 2D-liste:", org_content)

# Eksempel 1: standard parametre (se resultat i foo.csv)
write_csv_file("foo.csv", org_content)
with open("foo.csv", encoding='utf-8') as f:
    print("write_csv_file, standard parametre:", repr(f.read()))
readback_content = read_csv_file("foo.csv")
print("read_csv_file, standard parametre:", readback_content)

# Eksempel 2: eksempel på bruk av navngitte parametre (se resultat i bar.csv)
# delimiter="|" endrer skillesymbolet til vertikal strek
# quoting=csv.QUOTE_NONNUMERIC gjør at alt unntatt tall-verdier omsluttes
# av hermetegn; og ved lesing, at tall uten hermetegn konverteres til float.
write_csv_file("bar.csv", org_content, delimiter="|", 
                                       quoting=csv.QUOTE_NONNUMERIC)
with open("bar.csv", encoding='utf-8') as f:
    print("write_csv_file, med egne parametre:", repr(f.read()))
readback_content = read_csv_file("bar.csv", delimiter="|",
                                            quoting=csv.QUOTE_NONNUMERIC)
print("read_csv_file, med egne parametre:", readback_content)

import csv
from pathlib import Path

# Kopier gjerne funksjonene csv_dict_reader og csv_dict_writer herfra

def csv_dict_reader(path, encoding='utf-8', delimiter=',',
                    quotechar='"', quoting=csv.QUOTE_MINIMAL, **kwargs):
    '''Read a CSV file and return the headers as a list and the data as
    a list of dictionaries. Typical usage example:

        >>> headers, data = csv_dict_reader('foo.csv', delimiter=';')
        >>> headers
        ['Name', 'Age']
        >>> data
        [{'Name': 'Ola', 'Age': '74'}, {'Name': 'Kari', 'Age': '73'}]
    
    Args:
        path (str): The path to the CSV file.
        encoding (str, optional): The encoding of the CSV file. Default
            is 'utf-8'.
        delimiter (str, optional): The delimiter between cells used in
            the CSV file. Default is ','.
        quotechar (str, optional): The quote character used in the CSV
            file. Default is '"'.
        quoting (int, optional): The quoting style used in the CSV
            file. Default is csv.QUOTE_MINIMAL. Some other useful
            options are csv.QUOTE_ALL and csv.QUOTE_NONNUMERIC. See
            https://docs.python.org/3/library/csv.html#csv.QUOTE_ALL
            for more information.
        **kwargs: Additional keyword args to pass to csv.DictReader.

    Returns:
        headers (list): The headers of the CSV file.
        data (list): The data of the CSV file as a list of dictionaries.
    '''
    with Path(path).open('rt', encoding=encoding, newline='') as f:
        reader = csv.DictReader(f, delimiter=delimiter, quotechar=quotechar,
                                quoting=quoting, **kwargs)
        headers = reader.fieldnames
        data = list(reader)
    return headers, data

def csv_dict_writer(path, headers, data, encoding='utf-8', delimiter=',',
                    quotechar='"', quoting=csv.QUOTE_MINIMAL, **kwargs):
    '''Write a CSV file with the specified headers and data. Typical
    usage example:
    
        >>> headers = ['Name', 'Age']
        >>> data = [
        ...     {'Name': 'Ola', 'Age': 74},
        ...     {'Name': 'Kari', 'Age': 73},
        ... ]
        >>> csv_dict_writer('foo.csv', headers, data, delimiter=';')
            
    Args:
        path (str): The path to the CSV file.
        headers (list): The headers of the CSV file.
        data (list): The data of the CSV file as a list of dictionaries.
        encoding (str, optional): The encoding of the CSV file. Default
            is 'utf-8'.
        delimiter (str, optional): The delimiter between cells used in
            the CSV file. Default is ','.
        quotechar (str, optional): The quote character used in the CSV
            file. Default is '"'.
        quoting (int, optional): The quoting style used in the CSV
            file. Default is csv.QUOTE_MINIMAL. Some other useful
            options are csv.QUOTE_ALL and csv.QUOTE_NONNUMERIC. See
            https://docs.python.org/3/library/csv.html#csv.QUOTE_ALL
            for more information.
        **kwargs: Additional keyword args to pass to csv.DictWriter.

    Returns:
        None
    '''
    with Path(path).open('wt', encoding=encoding, newline='') as f:
        writer = csv.DictWriter(f, fieldnames=headers, delimiter=delimiter,
                                quotechar=quotechar, quoting=quoting)
        writer.writeheader()
        writer.writerows(data)

# Eksempel på bruk:
org_headers = ['Name', 'Age']
org_data = [
    {'Name': 'Ola', 'Age': 74},
    {'Name': 'Kari', 'Age': 73},
]

# Skriv til fil med ulike innstillinger med csv_dict_writer
csv_dict_writer('default.csv', org_headers, org_data)
csv_dict_writer('semicolon.csv', org_headers, org_data, delimiter=';')
csv_dict_writer('quotenonnumeric.csv', org_headers, org_data,
                quotechar="'", quoting=csv.QUOTE_NONNUMERIC)

# Les de produserte filene som rå tekst (plain text)
raw_csv_default = Path('default.csv').read_text(encoding='utf-8')
raw_csv_semicolon = Path('semicolon.csv').read_text(encoding='utf-8')
raw_csv_quotenumeric = Path('quotenonnumeric.csv').read_text(encoding='utf-8')

# Les de produserte filene tilbake med csv_dict_reader 
rb_default_headers, rb_default_data = csv_dict_reader('default.csv')
rb_semicolon_headers, rb_semicolon_data = csv_dict_reader(
    'semicolon.csv', delimiter=';'
)
rb_quotenumeric_headers, rb_quotenumeric_data = csv_dict_reader(
    'quotenonnumeric.csv', quotechar="'", quoting=csv.QUOTE_NONNUMERIC
)

print('Raw file content')
print('default:     ', repr(raw_csv_default))
print('semicolon:   ', repr(raw_csv_semicolon))
print('quotenumeric:', repr(raw_csv_quotenumeric))
# default:      'Name,Age\nOla,74\nKari,73\n'
# semicolon:    'Name;Age\nOla;74\nKari;73\n'
# quotenumeric: "'Name','Age'\n'Ola',74\n'Kari',73\n"

print()
print('Readback headers')
print('default:     ', rb_default_headers)
print('semicolon:   ', rb_semicolon_headers)
print('quotenumeric:', rb_quotenumeric_headers)
# rb_default:      ['Name', 'Age']
# rb_semicolon:    ['Name', 'Age']
# rb_quotenumeric: ['Name', 'Age']

print()
print('Readback data')
print('default:     ', rb_default_data)
print('semicolon:   ', rb_semicolon_data)
print('quotenumeric:', rb_quotenumeric_data)
# default:      [{'Name': 'Ola', 'Age': '74'}, {'Name': 'Kari', 'Age': '73'}]
# semicolon:    [{'Name': 'Ola', 'Age': '74'}, {'Name': 'Kari', 'Age': '73'}]
# quotenumeric: [{'Name': 'Ola', 'Age': 74.0}, {'Name': 'Kari', 'Age': 73.0}]

import csv
import io

csv_string = '''\
Name;Age
Ola;74
Kari;73
'''

# Leser fra en streng med DictReader
reader = csv.DictReader(io.StringIO(csv_string), delimiter=';')
headers = reader.fieldnames
data = list(reader)

print(headers) # ['Name', 'Age']
print(data)  # [{'Name': 'Ola', 'Age': '74'}, {'Name': 'Kari', 'Age': '73'}]