Compare and explain the return results of the lenb function and the len function

Comparison and explanation of the return results of the lenb function and the len function

In Python, we often use the len function to obtain the values ​​of containers such as strings, lists, and tuples. length. However, the len function may have some problems when it comes to Chinese characters, because the number of bytes occupied by Chinese characters in memory is not fixed. To solve this problem, Python provides a special function lenb.

The len function is a built-in function, its function is to return the number of elements in a container. For strings, it returns the number of characters in the string; for containers such as lists and tuples, it returns the number of elements in the container.

The lenb function is a very useful function when using Chinese characters. Its function is similar to the len function, but it returns the length of Chinese characters in bytes.

Let us compare and explain the return results of the lenb function and the len function through some specific code examples.

Example 1:

a = "Hello World"  # 英文字符串
b = "你好，世界"  # 中文字符串

print(len(a))  # 输出：11
print(lenb(a))  # 输出：11

print(len(b))  # 输出：5
print(lenb(b))  # 输出：15

In this example, we define two strings a and b. a is a string consisting of 11 English characters, and b is a string consisting of 5 Chinese characters. We use the len function and lenb function respectively to get the length of these two strings.

For the English string a, whether you use the len function or the lenb function, their return results are the same, which are the number of characters in the string, that is, 11.

But for the Chinese string b, the len function returns the number of characters, which is 5. This is because in Python, a Chinese character will be processed as a whole. The lenb function returns the length of Chinese characters in bytes, which is 15. This is because Chinese characters take up three bytes in memory.

Example 2:

c = ["苹果", "香蕉", "橙子"]  # 中文列表

print(len(c))  # 输出：3
print(lenb(c))  # 报错：TypeError: object of type 'list' has no len()

In this example, we define a Chinese list c, which contains 3 Chinese strings. We try to use the len function and lenb function to get the length of this list.

For the len function, it returns the number of elements in the list, which is 3.

But for the lenb function, it will report an error and prompt "TypeError: object of type 'list' has no len()". This is because the lenb function can only be used to process strings, and cannot be used to process other types of containers such as lists and tuples.

To sum up, there are some differences between the len function and the lenb function when processing Chinese characters. The len function returns the number of characters, while the lenb function returns the length of Chinese characters in bytes. When using Chinese characters, we can choose the appropriate function according to actual needs to obtain the correct length information.

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