十个 Python 变量检查与验证的简洁代码片段

def is_integer(value):
    """检查变量是否为整数"""
    return isinstance(value, int)

# 测试示例
print(is_integer(10))  # 输出: True
print(is_integer(10.5))  # 输出: False

def is_float(value):
    """检查变量是否为浮点数"""
    return isinstance(value, float)

# 测试示例
print(is_float(10.5))  # 输出: True
print(is_float(10))  # 输出: False

def is_string(value):
    """检查变量是否为字符串"""
    return isinstance(value, str)

# 测试示例
print(is_string("Hello"))  # 输出: True
print(is_string(10))  # 输出: False

def is_empty(value):
    """检查变量是否为空"""
    return value == "" or value is None

# 测试示例
print(is_empty(""))  # 输出: True
print(is_empty(None))  # 输出: True
print(is_empty("Hello"))  # 输出: False

def is_list(value):
    """检查变量是否为列表"""
    return isinstance(value, list)

# 测试示例
print(is_list([1, 2, 3]))  # 输出: True
print(is_list((1, 2, 3)))  # 输出: False

def is_tuple(value):
    """检查变量是否为元组"""
    return isinstance(value, tuple)

# 测试示例
print(is_tuple((1, 2, 3)))  # 输出: True
print(is_tuple([1, 2, 3]))  # 输出: False

def is_dict(value):
    """检查变量是否为字典"""
    return isinstance(value, dict)

# 测试示例
print(is_dict({"name": "Alice", "age": 30}))  # 输出: True
print(is_dict([1, 2, 3]))  # 输出: False

def is_bool(value):
    """检查变量是否为布尔值"""
    return isinstance(value, bool)

# 测试示例
print(is_bool(True))  # 输出: True
print(is_bool(1))  # 输出: False

def is_set(value):
    """检查变量是否为集合"""
    return isinstance(value, set)

# 测试示例
print(is_set({1, 2, 3}))  # 输出: True
print(is_set([1, 2, 3]))  # 输出: False

def is_function(value):
    """检查变量是否为函数"""
    return callable(value)

# 测试示例
def my_function():
    pass

print(is_function(my_function))  # 输出: True
print(is_function(10))  # 输出: False

def validate_user_input(username, age, email):
    """验证用户输入"""
    if not is_string(username) or username.strip() == "":
        return "Invalid username"
    
    if not is_integer(age) or age <= 0:
        return "Invalid age"
    
    if not is_string(email) or "@" not in email:
        return "Invalid email"
    
    return "All inputs are valid"

# 测试示例
print(validate_user_input("Alice", 30, "alice@example.com"))  # 输出: All inputs are valid
print(validate_user_input("", 30, "alice@example.com"))  # 输出: Invalid username
print(validate_user_input("Alice", -5, "alice@example.com"))  # 输出: Invalid age
print(validate_user_input("Alice", 30, "aliceexample.com"))  # 输出: Invalid email