text = "Hello, world!"  
substring = "world"  
  
if substring in text:  
    print(f"{substring} is found in the text.")  
else:  
    print(f"{substring} is not found in the text.")

text = "Hello, world! This is a Python tutorial."  
substrings = ["world", "Python", "Java"]  
  
found_substrings = []  
  
for substring in substrings:  
    if substring in text:  
        found_substrings.append(substring)  
  
if found_substrings:  
    print(f"The following substrings were found: {', '.join(found_substrings)}")  
else:  
    print("No substrings were found.")

text = "The price is $123.45"  
pattern = r"\d+\.\d+"  # 匹配浮點數(shù)的正則表達式  
  
match = re.search(pattern, text)  
if match:  
    print(f"Found: {match.group()}")  
else:  
    print("No match found.")

text = "Apple: 10, Banana: 20, Cherry: 30"  
pattern = r"\d+"  # 匹配數(shù)字的正則表達式  
  
matches = re.findall(pattern, text)  
if matches:  
    print(f"Found numbers: {', '.join(matches)}")  
else:  
    print("No numbers found.")

import re  
  
# 用戶信息字符串  
user_info = "User: alice, Email: alice@example.com, Phone: 123-456-7890"  
  
# 定義要查找的元素及其對應(yīng)的正則表達式模式  
elements_to_find = {  
    "username": r"User: (\w+)",  
    "email": r"Email: ([\w\.-]+@[\w\.-]+\.\w+)",  
    "phone": r"Phone: (\d{3}-\d{3}-\d{4})"  
}  
  
found_elements = {}  
  
# 使用正則表達式查找每個元素  
for element_name, pattern in elements_to_find.items():  
    match = re.search(pattern, user_info)  
    if match:  
        found_elements[element_name] = match.group(1)  # 獲取匹配組中的第一個元素（括號內(nèi)的部分）  
  
# 輸出結(jié)果  
if found_elements:
    print("Found elements:")  
for element_name, element_value in found_elements.items():  
    print(f"{element_name}: {element_value}")  
  
# 檢查是否有未找到的元素  
missing_elements = set(elements_to_find.keys()) - set(found_elements.keys())  
if missing_elements:  
    print(f"The following elements were not found: {', '.join(missing_elements)}")

pattern = re.compile(r"\d+")  # 預(yù)編譯正則表達式  
matches = pattern.findall(text)  # 使用預(yù)編譯的正則表達式進行搜索