วันที่ 19 — การจัดการไฟล์ (File Handling)

# syntax
open('filename', mode)
# mode
# 'r' = read,
# 'a'= append
# 'w' = write
# 'x' = create
# os
# 'b' = binary mode
# 't' = text mode (default)

f = open('./files/reading_file_example.txt')
print(f) # <_io.TextIOWrapper name='./files/reading_file_example.txt' mode='r' encoding='UTF-8'>

f = open('./files/reading_file_example.txt')
print(f.read()) # read the whole text

f = open('./files/reading_file_example.txt')
print(f.read(10)) # read the first 10 characters

f = open('./files/reading_file_example.txt')
print(f.readline()) # read only the first line

f = open('./files/reading_file_example.txt')
print(f.readlines()) # read all the text line by line and return a list of lines

f = open('./files/reading_file_example.txt')
lines = f.read().splitlines()
print(type(lines))
print(lines)

with open('./files/reading_file_example.txt') as f:
    lines = f.read().splitlines()
    print(type(lines))
    print(lines)

with open('./files/reading_file_example.txt','a') as f:
    f.write('This text has to be appended at the end')

with open('./files/writing_file_example.txt','w') as f:
    f.write('This text will be written in a newly created file')

import os
os.remove('./files/example.txt')

import os
if os.path.exists('./files/example.txt'):
    os.remove('./files/example.txt')
else:
    print('The file does not exist')

# dictionary
person_dct= {
    "name":"Asabeneh",
    "country":"Finland",
    "city":"Helsinki",
    "skills":["JavaScrip", "React","Python"]
}
# json.dumps converts python dictionary to json string
json_string = json.dumps(person_dct)
print(type(json_string))
print(json_string)

import json
# JSON
person_json = '''
{
    "name": "Asabeneh",
    "country": "Finland",
    "city": "Helsinki",
    "skills": ["JavaScrip", "React", "Python"]
}'''
# let us change JSON to dictionary
person_dct = json.loads(person_json)
print(type(person_dct))
print(person_dct)
print(person_dct['name'])

import json
person = {
    "name": "Asabeneh",
    "country": "Finland",
    "city": "Helsinki",
    "skills": ["JavaScrip", "React", "Python"]
}
with open('./files/json_example.json', 'w', encoding='utf-8') as f:
    json.dump(person, f, ensure_ascii=False, indent=4)

import csv
with open('./files/csv_example.csv') as f:
    csv_reader = csv.reader(f, delimiter=',')
    line_count = 0
    for row in csv_reader:
        if line_count == 0:
            print(f'Column names are {{", ".join(row)}}')
            line_count += 1
        else:
            print(
                f'\t{row[0]} is a teachers. He lives in {row[1]}, {row[2]}.')
            line_count += 1
    print(f'Number of lines:  {line_count}')

import xlrd
excel_book = xlrd.open_workbook('sample.xls')
print(excel_book.nsheets)
print(excel_book.sheet_names())

import xml.etree.ElementTree as ET
tree = ET.parse('./files/xml_example.xml')
root = tree.getroot()
print('Root tag:', root.tag)
print('Attribute:', root.attrib)
for child in root:
    print('field: ', child.tag)

# ผลลัพธ์ควรมีลักษณะดังนี้
print(most_spoken_languages(filename='./data/countries_data.json', 10))
[(91, 'English'),
(45, 'French'),
(25, 'Arabic'),
(24, 'Spanish'),
(9, 'Russian'),
(9, 'Portuguese'),
(8, 'Dutch'),
(7, 'German'),
(5, 'Chinese'),
(4, 'Swahili'),
(4, 'Serbian')]

# ผลลัพธ์ควรมีลักษณะดังนี้
print(most_spoken_languages(filename='./data/countries_data.json', 3))
[(91, 'English'),
(45, 'French'),
(25, 'Arabic')]

# ผลลัพธ์ควรมีลักษณะดังนี้
print(most_populated_countries(filename='./data/countries_data.json', 10))

[
{'country': 'China', 'population': 1377422166},
{'country': 'India', 'population': 1295210000},
{'country': 'United States of America', 'population': 323947000},
{'country': 'Indonesia', 'population': 258705000},
{'country': 'Brazil', 'population': 206135893},
{'country': 'Pakistan', 'population': 194125062},
{'country': 'Nigeria', 'population': 186988000},
{'country': 'Bangladesh', 'population': 161006790},
{'country': 'Russian Federation', 'population': 146599183},
{'country': 'Japan', 'population': 126960000}
]

# ผลลัพธ์ควรมีลักษณะดังนี้
print(most_populated_countries(filename='./data/countries_data.json', 3))
[
{'country': 'China', 'population': 1377422166},
{'country': 'India', 'population': 1295210000},
{'country': 'United States of America', 'population': 323947000}
]

# ผลลัพธ์ควรมีลักษณะดังนี้
print(find_most_common_words('sample.txt', 10))
[(10, 'the'),
(8, 'be'),
(6, 'to'),
(6, 'of'),
(5, 'and'),
(4, 'a'),
(4, 'in'),
(3, 'that'),
(2, 'have'),
(2, 'I')]

# ผลลัพธ์ควรมีลักษณะดังนี้
print(find_most_common_words('sample.txt', 5))

[(10, 'the'),
(8, 'be'),
(6, 'to'),
(6, 'of'),
(5, 'and')]