Add some examples

- these may be helpful when explaining/understanding a concept.

Author: abhiabhi94

examples

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+import os
+
+
+current_working_dir = os.getcwd()
+
+# change working directory
+# junk_dir = os.path.join(current_working_dir, 'junk')
+# os.chdir(junk_dir)
+# print(os.getcwd())
+
+
+# rename directories
+
+# os.rename('my_dir', 'renamed_dir')
+
+
+# move directories with replace
+# os.replace('renamed_dir/junk', 'abcd')
+
+
+# remove, rmdir, rmdirs

examples/change_dirs.py

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+with open('meme.jpg', 'rb') as original_file:
+    with open('meme_copy.jpg', 'wb') as copy_file:
+        for line in original_file:
+            copy_file.write(line)

examples/copy_file.py

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+Ada Lovelace: 834.345.1254 155-Street London, England
+Tessy Thomas: 892.345.3428 436-Street Alappuzha, Kerala
+Ritu Karidhal: 925.541.7625 662-Street Lucknow, Uttar Pradesh
+Muthayya Vanitha: 548-326-4584 919-Street Chennai, India

examples/data.txt

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+import os
+
+print(__file__)
+
+here_relative = os.path.relpath(__file__)
+here_real = os.path.realpath(__file__)
+
+parent_dir = os.path.dirname(here_real)
+
+text_file_loc = os.path.join(parent_dir, 'text.txt')
+
+all_files = os.listdir(os.getcwd())

examples/dirs.py

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+Just trying to test sending some text.
+
+These contents were picked up from a file.
+
+It seems learning python could be a lot more fun.

examples/emails/email.txt

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+To: Bar <receiver@domain>
+From: Foo <sender@domain>
+Subject: Testing parsing headers from text template
+
+Wow! This is exceptional
+
+We can send emails by parsing text from a file.

examples/emails/email_headers.txt

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+import smtplib
+import os
+from email.parser import BytesParser
+from email.policy import default
+
+
+BASE_DIR = os.path.dirname(os.path.abspath(__file__))
+HEADERS_PATH = os.path.join(BASE_DIR, 'email_headers.txt')
+
+with open(HEADERS_PATH, 'rb') as fp:
+    message = BytesParser(policy=default).parse(fp)
+
+with smtplib.SMTP('localhost', 1025) as server:
+    server.send_message(message)

examples/emails/parse_headers.py

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+import smtplib, ssl
+from email.message import EmailMessage
+import imghdr
+import os
+import mimetypes
+
+
+
+BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+PATH = os.path.join(BASE_DIR, 'meme.jpg')
+
+sender = os.getenv('EMAIL_SENDER')
+
+msg = EmailMessage()
+msg['to'] = os.getenv('EMAIL_RECEIVER')
+msg['from'] = sender
+msg['subject'] = 'Test sending attachments through python'
+msg.preamble = 'You will not see this in a MIME-aware mail reader.\n'
+msg.set_content('Please find the image attached below.')
+
+
+with open(PATH, 'rb') as fp:
+    img_data = fp.read()
+
+# Guess the content type based on the file's extension.  Encoding
+# will be ignored, although we should check for simple things like
+# gzip'd or compressed files.
+ctype, encoding = mimetypes.guess_type(PATH)
+if ctype is None or encoding is not None:
+    # No guess could be made, or the file is encoded (compressed), so
+    # use a generic bag-of-bits type.
+    ctype = 'application/octet-stream'
+maintype, subtype = ctype.split('/', 1)
+
+msg.add_attachment(img_data, maintype=maintype, subtype=subtype)
+
+with smtplib.SMTP_SSL('smtp.gmail.com', 465) as server:
+    try:
+        server.login(sender, os.getenv('EMAIL_PASS'))
+        server.send_message(msg)
+
+    except smtplib.SMTPResponseException as exc:
+        print('Exception occured during sending of email:', exc)

examples/emails/send_attachments_real.py

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+import smtplib
+from email.message import EmailMessage
+import os
+
+
+BASE_DIR = os.path.dirname(os.path.abspath(__file__))
+HTML_PATH = os.path.join(BASE_DIR, 'email.html')
+
+msg = EmailMessage()
+msg['To'] = 'receiver@domain'
+msg['From'] = 'sender@domain'
+msg['Subject'] = 'Testing large HTML email'
+msg.set_content('This is the text portion')
+
+with open(HTML_PATH) as fp:
+    msg.add_alternative(fp.read(), subtype='html')
+
+
+with smtplib.SMTP('localhost', 1025) as server:
+    server.send_message(msg)

examples/emails/send_html.py

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+import smtplib
+from email.message import EmailMessage
+import os
+
+
+BASE_DIR = os.path.dirname(os.path.abspath(__file__))
+HTML_PATH = os.path.join(BASE_DIR, 'email.html')
+
+
+msg = EmailMessage()
+msg['To'] = os.getenv('EMAIL_RECEIVER')
+msg['From'] = sender = os.getenv('EMAIL_SENDER')
+msg['Subject'] = 'Testing large HTML email'
+
+with open(HTML_PATH) as fp:
+    msg.add_alternative(fp.read(), subtype='html')
+
+with smtplib.SMTP_SSL('smtp.gmail.com', 465) as server:
+    server.login(sender, os.getenv('EMAIL_PASS'))
+    server.send_message(msg)

examples/emails/send_html_real.py

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+import smtplib, ssl
+from email.message import EmailMessage
+import imghdr
+import os
+
+
+BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+IMG_PATH = os.path.join(BASE_DIR, 'meme.jpg')
+
+
+msg = EmailMessage()
+msg['to'] = os.getenv('EMAIL_RECEIVER')
+msg['from'] = sender = os.getenv('EMAIL_SENDER')
+msg['subject'] = 'Test sending attachments through python'
+msg.preamble = 'You will not see this in a MIME-aware mail reader.\n'
+msg.set_content('Please find the image attached below.')
+
+with open(IMG_PATH, 'rb') as fp:
+    img_data = fp.read()
+
+msg.add_attachment(img_data, maintype='image', subtype=imghdr.what(None, img_data))
+
+with smtplib.SMTP_SSL('smtp.gmail.com', 465) as server:
+    try:
+        server.login(sender, os.getenv('EMAIL_PASS'))
+        server.send_message(msg)
+
+    except smtplib.SMTPResponseException as exc:
+        print('Exception occured during sending of email:', exc)

examples/emails/send_image_real.py

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+import smtplib
+from email.message import EmailMessage
+
+
+msg = EmailMessage()
+msg['to'] = 'receiver@domain'
+msg['from'] = 'sender@domain'
+msg['subject'] = 'Test sending text emails from python'
+msg.set_content('Hi! just checking to see if this works')
+
+
+with smtplib.SMTP('localhost', 1025) as server:
+    server.send_message(msg)

examples/emails/send_text.py

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+import smtplib
+from email.message import EmailMessage
+import os
+
+
+BASE_DIR = os.path.dirname(os.path.abspath(__file__))
+TEXT_PATH = os.path.join(BASE_DIR, 'email.txt')
+
+msg = EmailMessage()
+msg['To'] = 'receiver@domain'
+msg['From'] = 'sender@domain'
+msg['Subject'] = 'Testing largetext from python'
+
+with open(TEXT_PATH) as fp:
+    msg.set_content(fp.read())
+
+with smtplib.SMTP('localhost', 1025) as server:
+    server.send_message(msg)

examples/emails/send_text_from_file.py

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+import smtplib
+from email.message import EmailMessage
+import os
+
+
+msg = EmailMessage()
+msg['from'] = sender = os.getenv('EMAIL_SENDER')
+msg['to'] = os.getenv('EMAIL_RECEIVER')
+msg['subject'] = 'Testing text email through python'
+msg.set_content('Hi! let us hope this works.')
+
+with smtplib.SMTP_SSL('smtp.gmail.com') as server:
+    server.login(sender, os.getenv('EMAIL_PASS'))
+    server.send_message(msg)

examples/emails/send_text_real.py

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+with open('text.txt', 'r') as f:
+    for num, line in enumerate(f):
+        if line.find('text') > -1:
+            print(f'The word text is present on the line {num + 1}')
+
+
+# print(content)

examples/files.py

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+import re
+
+
+text = '''
+this is a long string
+
+a multi line string
+
+46833
+
+special characters that need to be escaped
+. * ^ + ? | [ ] { }
+
+'''
+pattern = re.compile(r'\d{3}[\.-]\d{3}[\.-]\d{4}')
+
+with open('data.txt') as f:
+    for line in f:
+        matches = pattern.finditer(line)
+        for match in matches:
+            print(match)
+# sentence = 'this is a SENTENCE 23'
+# sentence = 'aababcaabaaabc'
+# pattern = re.compile(r'a?')
+
+# matches = pattern.finditer(sentence)
+# for match in matches:
+#     print(match)

examples/meme.jpg

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+import os
+
+
+cwd = os.chdir('/home/curious/Desktop/temp/module/junk')
+
+
+def create(prefix='file', extension='txt'):
+    for num in range(1, 1001):
+        filename = f'{prefix}_{num}.{extension}'
+        with open(filename, 'x'):
+            pass
+
+
+def rename():
+    filenames = os.listdir(cwd)
+    # 01_file.txt
+    for filename in filenames:
+        name, extension = filename.split('.')
+        name, num = name.split('_')
+
+        num = num.zfill(2)
+        os.rename(filename, f'{num}_{name}.{extension}')
+
+
+
+def delete():
+    filenames = os.listdir(cwd)
+    for filename in filenames:
+        os.remove(filename)

examples/meme_copy.jpg

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+import socket
+
+
+HOST = socket.gethostbyname(socket.gethostname())
+PORT = 9999
+
+with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as client:
+    client.connect((HOST, PORT))
+
+    client.sendall('Hi'.encode())
+    data = client.recv(1024)
+    print(f'Received from the server: {data.decode()}')

examples/regular_expression.py

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+import socket
+import concurrent.futures
+
+
+HOST = socket.gethostbyname(socket.gethostname())
+PORT = 9999
+
+
+def handle_client(conn, addr):
+    with conn:
+        print(f'Connected from client:{addr}')
+        while True:
+            msg = conn.recv(1024)
+            if not msg:
+                print(f'Connection closed from {addr}')
+                break
+            print(f'Received: {msg.decode()}')
+            conn.sendall('Hi from server'.encode())
+
+with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as server:
+    server.bind((HOST, PORT))
+    server.listen()
+    print(f'Server is listening at {HOST}:{PORT}')
+    while True:
+        conn, addr = server.accept()
+        with concurrent.futures.ThreadPoolExecutor() as executor:
+            executor.submit(handle_client, conn, addr)

examples/rename.py

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+Special characters in default mode.
+
+
+. - matches every character except newline
+\w - every character(a-z, A-Z, 0-9,_)
+\W - not a character
+\d - digit
+\D - not a digit
+\s - space character(including tabs and newlines)
+\S - not a space character
+
+
+\b - boundary of a word
+\B - not a boundary
+^ - starting of the string
+$ - ending of the string
+
+[]      - Matches Characters in brackets
+[^ ]    - Matches Characters NOT in brackets
+|       - Either Or
+( )     - Group
+
+Quantifiers
+-----------
+
+* - causes the preceding RE to match 0 or more times.
++ - preceding RE matches atleast 1 time.
+? - preceding RE matches 0 or 1 time.
+{m} - preceding RE matches exactly m times.
+{m, n} - preceding RE matches atleast m times and atmost n times.