Python's len function is used to calculate the size of objects such as strings, lists, and tuples.

The len function in Python is used to calculate the length of strings, lists, tuples and other objects

In Python, we often need to know a string, The length of an object such as a list or tuple so that the corresponding operation can be performed. At this time, we can use the len function to help us calculate the length of the object.

The len function is one of Python's built-in functions. Its function is to return the length of a given object. It works on strings, lists, tuples, and other objects that support sequence operations. When using the len function, you need to pass the object to be calculated as a parameter to the function, and then the function will return the length of the object.

The following are some specific code examples to show the use and effect of the len function:

1. Calculate the length of the string

str1 = "Hello World"
length = len(str1)
print("字符串的长度为：", length)

Output:

字符串的长度为： 11

2. Calculate the length of the list

list1 = [1, 2, 3, 4, 5]
length = len(list1)
print("列表的长度为：", length)

Output:

列表的长度为： 5

3. Calculate the length of the tuple

tuple1 = (1, 2, 3, 4, 5)
length = len(tuple1)
print("元组的长度为：", length)

Output:

元组的长度为： 5

In addition to strings, lists, and tuples, the len function can also be used for other objects that support sequence operations, such as sets and dicts. For a collection, the len function will return the number of elements in the collection; for a dictionary, the len function will return the number of key-value pairs in the dictionary.

4. Calculate the length of the set

set1 = {1, 2, 3, 4, 5}
length = len(set1)
print("集合的长度为：", length)

Output:

集合的长度为： 5

5. Calculate the length of the dictionary

dict1 = {"name": "Tom", "age": 25, "gender": "male"}
length = len(dict1)
print("字典的长度为：", length)

Output:

字典的长度为： 3

It should be noted that the len function can only be used for immutable objects. For length calculations of variable objects (such as lists and dictionaries), whether the object has changed must also be considered. If the object is modified before the len function calculates the length, the length returned by the len function will be the length before the modification.

Summary:

The len function is a function used in Python to calculate the length of objects such as strings, lists, and tuples. It can easily obtain the number of elements in the object. Its use is very simple, just pass the object to be calculated to the len function. Whether it is a string, list, tuple, set or dictionary, we can use the len function to calculate their length.

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