Python新手：理解TypeError的十个实例-向日葵屋

Python新手：理解TypeError的十个实例

TypeError是Python中一种常见的运行时错误。它通常发生在尝试对某种类型的数据执行不兼容的操作时。以下是十个理解TypeError的实例：

数字与字符串混合:

num = 5
str = "hello"
print(num + str)  # TypeError: can only concatenate str (not "int") to str

错误地将列表赋给字典:

list_data = ['apple', 'banana', 'cherry']
dict_data = {'fruit': list_data}  # TypeError: '<list>' object does not support item assignment
dict_data = {key: value for key, value in list_data.items()}  # Correct way to assign a list to a dictionary

尝试对非数字类型进行数学运算:

str_num = "12"
float_num = 5.6
try_addition = str_num + float_num  # TypeError: can only concatenate str (not "int") to str

混合使用序列（如列表和元组）:

list_data = [1, 'apple', 3.14],  # Mixed use of sequence types
try_access_value = list_data[0][2]]  # TypeError: list indices must be integers or slices, not tuple

错误地将字典的值赋给变量:

dict_data = {'name': 'John', 'age': 30}
value_assignment = dict_data['name'] = "Jane"  # TypeError: assignment destination must be a sequence

使用不兼容的类型进行比较:

int_num = 5
str_num = "10"
try_comparison = int_num > str_num  # TypeError: cannot compare types 'int' and 'str'

使用*操作符将元组与列表混合:

tuple_data = (1, 'apple', 3.14))
list_data = [5, 'banana', 6.28]]
mixed_product = tuple_data * list_data  # TypeError: can only concatenate list (not "tuple")) to list

尝试使用``操作符提取字典的值（Python 3.7 及以后版本）：

dict_data = {'name': 'John', 'age': 30}
extracted_value = dict_data ** 1  # TypeError: unsupported operand type(s) for **: 'dict' and 'int'

错误地使用+操作符连接两个不同类型的对象:

 int_num = 5
 str_num = "10"
 combined_type = int_num + str_num  # TypeError: can only concatenate str (not "int")) to str

尝试使用列表推导式（List Comprehension）创建一个字典，其中的值是另一个字典中的键:
```python
dict_data = {‘first_key’: ‘value1’, ‘second_key’: ‘value2’} # Original dictionary

wrong_comprehension = {key: dict_data[key] for key in dict_data} # Error: Wrong usage of list comprehension. Result is a set, not a dictionary.

correct_comprehension = {key: value for key, value in dict_data.items()} # Correct way to create a dictionary with values from another dictionary

print(wrong_comprehension) # Output: {‘first_key’: ‘value1’, ‘second_key’: ‘value2’}}