Metode String

# Demonstrasi sifat immutable strings = "hello"print(f"String awal: {s}")# Mencoba mengubah karakter secara langsungtry:  s[1] = "a"  # Ini akan menyebabkan errorexcept TypeError as e:  print(f"Error: {e}")# Cara yang benar: membuat string barus_new = s[:1] + "a" + s[2:]print(f"String baru: {s_new}")# String asli tetap tidak berubahprint(f"String asli masih: {s}")

# Mengukur panjang berbagai jenis stringstrings = [  "hello",  "Hello World!",  "Python programming",  "",  # string kosong  "   ",  # string berisi spasi  "123456"]for s in strings:  print(f"'{s}' memiliki panjang: {len(s)}")# Panjang string dengan karakter khususspecial = "Hello\nWorld\t!"print(f"String dengan escape sequence: {len(special)} karakter")print(f"Tampilan string: {repr(special)}")

# Contoh transformasi case pada stringtext = "Python Programming Language"# Mengubah ke huruf besar semuaupper_text = text.upper()print(f"Upper: {upper_text}")# Mengubah ke huruf kecil semualower_text = text.lower()print(f"Lower: {lower_text}")# Title case: huruf pertama setiap kata besartitle_text = text.title()print(f"Title: {title_text}")# Contoh dengan string campuranmixed = "hELLo WoRLd PyThOn"print(f"Original: {mixed}")print(f"Title case: {mixed.title()}")# Title case pada string dengan angka dan simbolcomplex_text = "python3.9 is-awesome!"print(f"Complex title: {complex_text.title()}")

# Demonstrasi berbagai metode striptext = "   Hello World   "print(f"Original: '{text}'")# Menghapus spasi di kedua sisistripped = text.strip()print(f"Strip: '{stripped}'")# Menghapus spasi hanya di kirileft_stripped = text.lstrip()print(f"Left strip: '{left_stripped}'")# Menghapus spasi hanya di kananright_stripped = text.rstrip()print(f"Right strip: '{right_stripped}'")# Strip dengan karakter khususspecial_text = "+++Hello World+++"custom_stripped = special_text.strip("+")print(f"Custom strip: '{custom_stripped}'")# Strip multiple charactersmessy_text = "---+++Hello World+++---"clean_text = messy_text.strip("-+")print(f"Multiple char strip: '{clean_text}'")

# Pencarian substring dengan berbagai metodetext = "Python is a powerful programming language"# Menggunakan index() - akan error jika tidak ditemukantry:  pos = text.index("powerful")  print(f"'powerful' ditemukan di posisi: {pos}")    # Mencari yang tidak ada  pos_not_found = text.index("Java")except ValueError as e:  print(f"Error dengan index(): {e}")# Menggunakan find() - mengembalikan -1 jika tidak ditemukanpos_find = text.find("powerful")print(f"find('powerful'): {pos_find}")pos_not_found = text.find("Java")print(f"find('Java'): {pos_not_found}")# Pencarian dengan parameter start dan endsubstring = "programming"start_pos = text.find(substring, 20)  # mulai dari posisi 20print(f"'{substring}' setelah posisi 20: {start_pos}")# Menghitung kemunculan substringcount = text.count("a")print(f"Huruf 'a' muncul {count} kali")

# Contoh validasi berbagai jenis karaktertest_strings = [  "Python",  "Python3",  "12345",  "Hello World",  "hello123",  "UPPERCASE",  "lowercase",  "",  "   "]print("String\t\tAlpha\tDigit\tAlnum\tUpper\tLower")print("-" * 60)for s in test_strings:  alpha = s.isalpha()  digit = s.isdigit()  alnum = s.isalnum()  upper = s.isupper()  lower = s.islower()    print(f"'{s:<10}'\t{alpha}\t{digit}\t{alnum}\t{upper}\t{lower}")# Contoh penggunaan praktis untuk validasi inputdef validate_username(username):  if not username:      return "Username tidak boleh kosong"  if not username.isalnum():      return "Username hanya boleh berisi huruf dan angka"  if len(username) < 3:      return "Username minimal 3 karakter"  return "Username valid"# Test validasiusernames = ["user123", "user@123", "ab", "ValidUser"]for username in usernames:  result = validate_username(username)  print(f"'{username}': {result}")

# Contoh penggunaan startswith dan endswithfiles = [  "document.pdf",  "image.jpg",  "script.py",  "data.csv",  "README.md",  "backup.zip"]# Memeriksa ekstensi fileprint("File dengan ekstensi tertentu:")for file in files:  if file.endswith(".py"):      print(f"Python file: {file}")  elif file.endswith((".jpg", ".png", ".gif")):      print(f"Image file: {file}")  elif file.endswith(".pdf"):      print(f"PDF file: {file}")# Memeriksa awalanurls = [  "https://www.google.com",  "http://example.com",  "ftp://files.example.com",  "mailto:user@example.com"]print("\nAnalisis URL:")for url in urls:  if url.startswith("https://"):      print(f"Secure web: {url}")  elif url.startswith("http://"):      print(f"Web: {url}")  elif url.startswith("ftp://"):      print(f"FTP: {url}")  elif url.startswith("mailto:"):      print(f"Email: {url}")# Penggunaan dengan tuple untuk multiple prefix/suffixtext = "Hello World"print(f"\nStarts with greeting: {text.startswith(('Hi', 'Hello', 'Hey'))}")

# Contoh penggunaan metode replacetext = "Python is great. Python is powerful. Python is easy."print(f"Original: {text}")# Replace semua kemunculanreplaced = text.replace("Python", "Java")print(f"Replace all: {replaced}")# Replace dengan batasan jumlahlimited_replace = text.replace("Python", "Java", 2)print(f"Replace 2 first: {limited_replace}")# Replace dengan string kosong (menghapus)no_dots = text.replace(".", "")print(f"Remove dots: {no_dots}")# Chaining replace untuk multiple replacementssentence = "I love cats and dogs"animal_replace = sentence.replace("cats", "birds").replace("dogs", "fish")print(f"Chain replace: {animal_replace}")# Replace case-sensitivecase_text = "Hello hello HELLO"case_replace = case_text.replace("hello", "hi")print(f"Case sensitive: {case_replace}")# Contoh praktis: membersihkan nomor teleponphone = "+62-812-3456-7890"clean_phone = phone.replace("-", "").replace("+", "")print(f"Clean phone: {clean_phone}")

# Berbagai cara menggunakan splittext = "apple,banana,orange,grape"print(f"Original: {text}")# Split dengan delimiter komafruits = text.split(",")print(f"Split by comma: {fruits}")# Split tanpa parameter (default whitespace)sentence = "Python is a great language"words = sentence.split()print(f"Split by space: {words}")# Split dengan batasanlimited_split = text.split(",", 2)print(f"Split max 2: {limited_split}")# Split dengan multiple whitespacemessy_text = "word1    word2\t\tword3\n\nword4"clean_split = messy_text.split()print(f"Clean split: {clean_split}")# Contoh praktis: parsing data CSVcsv_line = "John,25,Engineer,New York"data = csv_line.split(",")name, age, job, city = dataprint(f"Name: {name}, Age: {age}, Job: {job}, City: {city}")# Split dengan karakter yang tidak adano_delimiter = "no-delimiter-here"result = no_delimiter.split(",")print(f"No delimiter found: {result}")# Menggabungkan kembali dengan joinjoined = " | ".join(fruits)print(f"Joined with pipe: {joined}")

# Contoh method chaining pada stringmessy_input = "   +++ Python Programming for Beginners ---   "print(f"Input: '{messy_input}'")# Chaining multiple methodsclean_result = (messy_input              .strip()  # hapus spasi di awal/akhir              .strip("+-")  # hapus karakter + dan -              .lower()  # ubah ke lowercase              .replace("beginners", "experts"))  # ganti kataprint(f"Clean result: '{clean_result}'")# Contoh chaining untuk format namanames = ["  JOHN DOE  ", "  jane SMITH  ", "  BOB johnson  "]formatted_names = []for name in names:  formatted = name.strip().title()  formatted_names.append(formatted)print("Formatted names:")for name in formatted_names:  print(f"- {name}")# Chaining dalam list comprehensionsentences = [  "  hello WORLD  ",  "  PYTHON programming  ",  "  DATA science  "]processed = [s.strip().title() for s in sentences]print(f"Processed sentences: {processed}")# Contoh chaining untuk validasi dan formattingdef process_email(email):  return email.strip().lower().replace(" ", "")emails = ["  USER@EXAMPLE.COM  ", "Test User@Gmail.com", "admin@site.org"]for email in emails:  processed = process_email(email)  print(f"'{email}' -> '{processed}'")

# Aplikasi praktis metode string dalam berbagai skenario# 1. Validasi dan format nomor telepondef format_phone_number(phone):  # Hapus semua karakter non-digit  digits_only = ""  for char in phone:      if char.isdigit():          digits_only += char    # Format sesuai standar Indonesia  if len(digits_only) == 13 and digits_only.startswith("62"):      return f"+{digits_only[:2]}-{digits_only[2:5]}-{digits_only[5:9]}-{digits_only[9:]}"  elif len(digits_only) == 12 and digits_only.startswith("08"):      return f"{digits_only[:4]}-{digits_only[4:8]}-{digits_only[8:]}"  else:      return "Format nomor tidak valid"phone_numbers = ["081234567890", "+6281234567890", "0812-3456-7890"]for phone in phone_numbers:  formatted = format_phone_number(phone)  print(f"'{phone}' -> '{formatted}'")# 2. Ekstrak informasi dari nama filedef analyze_filename(filename):  # Pisahkan nama dan ekstensi  if "." in filename:      name, ext = filename.rsplit(".", 1)      ext = ext.lower()  else:      name, ext = filename, ""    # Analisis jenis file  image_exts = ["jpg", "jpeg", "png", "gif", "bmp"]  doc_exts = ["pdf", "doc", "docx", "txt"]  code_exts = ["py", "js", "html", "css", "java"]    if ext in image_exts:      file_type = "Image"  elif ext in doc_exts:      file_type = "Document"  elif ext in code_exts:      file_type = "Code"  else:      file_type = "Unknown"    return {      "name": name,      "extension": ext,      "type": file_type,      "length": len(filename)  }files = ["photo.jpg", "report.pdf", "script.py", "data", "image.PNG"]for file in files:  info = analyze_filename(file)  print(f"{file}: {info}")# 3. Parser sederhana untuk log filedef parse_log_entry(log_line):  # Format: [TIMESTAMP] LEVEL: MESSAGE  if not log_line.strip():      return None    # Ekstrak timestamp  if log_line.startswith("[") and "]" in log_line:      end_bracket = log_line.index("]")      timestamp = log_line[1:end_bracket]      rest = log_line[end_bracket + 1:].strip()  else:      timestamp = "Unknown"      rest = log_line.strip()    # Ekstrak level  if ":" in rest:      level, message = rest.split(":", 1)      level = level.strip()      message = message.strip()  else:      level = "INFO"      message = rest    return {      "timestamp": timestamp,      "level": level,      "message": message  }log_entries = [  "[2023-09-17 10:30:15] ERROR: Database connection failed",  "[2023-09-17 10:30:16] INFO: Retrying connection",  "WARNING: Low disk space",  ""]print("\nLog parsing results:")for entry in log_entries:  parsed = parse_log_entry(entry)  if parsed:      print(f"Time: {parsed['timestamp']}, Level: {parsed['level']}, Message: {parsed['message']}")# 4. Pembuat slug URL dari juduldef create_slug(title):  # Konversi ke lowercase dan ganti spasi dengan dash  slug = title.lower()    # Ganti karakter non-alphanumeric dengan dash  clean_slug = ""  for char in slug:      if char.isalnum():          clean_slug += char      elif char == " " or not char.isalnum():          if clean_slug and clean_slug[-1] != "-":              clean_slug += "-"    # Hapus dash di awal dan akhir  return clean_slug.strip("-")titles = [  "Belajar Python untuk Pemula",  "Tips & Trik Programming",  "Data Science: Panduan Lengkap",  "Machine Learning 101"]print("\nSlug generation:")for title in titles:  slug = create_slug(title)  print(f"'{title}' -> '{slug}'")