How to use the str() function in Python to convert an object to a string

How to use the str() function in Python to convert an object into a string

In Python, the str() function is a very useful function that allows us Convert other types of objects to string types for printing or other string processing operations. This article will explain how to use the str() function to convert different types of objects into strings and provide some sample code.

1. Convert numbers to strings
   When we need to convert numbers to strings, we can use the str() function. For example:

num = 123
string_num = str(num)
print(string_num, type(string_num))

The output result is:

123 <class 'str'>

2. Convert list to string
   List is one of the commonly used data structures in Python. Sometimes we need to convert Convert the list to a string for printing or saving. Lists can be converted to strings using the str() function. For example:

my_list = [1, 2, 3, 4, 5]
string_list = str(my_list)
print(string_list, type(string_list))

The output is:

[1, 2, 3, 4, 5] <class 'str'>

3. Convert tuple to string
   Tuple is another commonly used data structure, similar to a list , but tuples are immutable. Similarly, we can also use the str() function to convert a tuple into a string. For example:

my_tuple = (1, 2, 3, 4, 5)
string_tuple = str(my_tuple)
print(string_tuple, type(string_tuple))

The output result is:

(1, 2, 3, 4, 5) <class 'str'>

4. Convert dictionary to string
   Dictionary is a very commonly used data structure in Python, which consists of key-value pairs constitute. We can convert dictionary to string using str() function. For example:

my_dict = {'name': 'Alice', 'age': 18, 'gender': 'female'}
string_dict = str(my_dict)
print(string_dict, type(string_dict))

The output result is:

{'name': 'Alice', 'age': 18, 'gender': 'female'} <class 'str'>

It should be noted that the form after converting the dictionary to a string is a special format and it is not an exact representation of the dictionary. .

5. Using the str() function in custom classes
   We can also override the __str__() method in custom classes to define how objects are converted to strings. For example:

class Person:
    def __init__(self, name, age):
        self.name = name
        self.age = age
    
    def __str__(self):
        return f"Person(name={self.name}, age={self.age})"

person = Person("Alice", 18)
string_person = str(person)
print(string_person, type(string_person))

The output result is:

Person(name=Alice, age=18) <class 'str'>

By rewriting the __str__() method, we can make the printed results more consistent with our needs.

To sum up, the str() function is a very practical function in Python, which allows us to convert different types of objects into strings. We can convert various types of objects such as numbers, lists, tuples, and dictionaries into strings through the str() function to facilitate print output or other string processing operations. In a custom class, we can also define how the object is converted to a string by overriding the __str__() method. Mastering the usage of str() function is very important for daily programming.

I hope this article can help readers better understand and use the str() function. It should be noted that the sample code in this article can be tried in the interactive environment of Python and extended and modified according to your own needs. Happy programming everyone!

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