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Updated on 2025-05-15

Detailed explanation of the basic method of Python processing Unicode strings

In modern programming, processing strings is one of the very common tasks. With the development of globalization, the processing of Unicode strings has become particularly important. Python, as a widely used high-level programming language, provides powerful support for handling Unicode strings. This article will introduce some basic methods for handling Unicode strings in Python.

What is Unicode

Unicode is an international standard used to represent almost all characters in the world. It assigns a unique number to each character, called a code point. For example, the Unicode code point of the Chinese character "middle" is U+4E2D. Python strings are encoded by default, which means you can directly handle characters from various languages.

String types in Python

In Python 3, the string type is str and is encoded by default using UTF-8. UTF-8 is a variable-length encoding that can effectively represent Unicode characters. In addition, Python also provides the bytes type, which is used to process raw byte data.

Create a Unicode string

Creating a Unicode string is very simple. You can wrap the string content directly in quotes, and Python will automatically treat it as a Unicode string.

 # Create a simple Unicode strings = "Hello, the world!"
print(s)  # Output: Hello, World!

If you need to process multilingual characters, you can put them directly into the string, which Python will automatically recognize and process correctly.

Access characters and substrings

Python provides a variety of ways to access characters and substrings in strings.

s = "Hello, the world!"
 
# Access single characterprint(s[0])  # Output: H 
# Get substringprint(s[7:])  # Output: World!

It should be noted that Python's string index starts at 0 and supports negative indexing.

String operation

Python provides many built-in functions and methods to manipulate strings. Here are some commonly used string operations:

  • len(): Returns the length of the string.
  • upper(): Converts a string to uppercase.
  • lower(): Converts a string to lowercase.
  • replace(): Replace the substring in the string.
  • split(): Split string by specified delimiter.
s = "Hello, the world!"
 
# Get string lengthprint(len(s))  # Output: 9 
# Convert to capitalprint(())  # Output: HELLO, World! 
# Replace charactersprint(("world", "Python"))  # Output: Hello, Python!

Handle Unicode encoding and decoding

Although Python strings are encoded by default, in some cases you may need to encode and decode manually.

 # Encode the string into bytess = "Hello, the world!"
encoded = ('utf-8')
print(encoded)  # Output: b'Hello, \xe4\xb8\x96\xe7\x95\x8c!' 
# Decode bytes into a stringdecoded = ('utf-8')
print(decoded)  # Output: Hello, World!

When encoding and decoding, it is important to ensure that the encoding format used is consistent with the actual data.

Knowledge Supplement

Conversion between string and unicode characters

def unicode_to_str(unicode_str):
    return unicode_str.encode().decode('unicode_escape')


def str_to_unicode(string):
    new_str = ''
    for ch in string:
        if '\u4e00' <= ch <= '\u9fff':
            new_str += hex(ord(ch)).replace('0x', '\\u')
        else:
            new_str += ch
    return new_str


if __name__ == '__main__':
    unicode = str_to_unicode('Hello')

    print(unicode) # \u4f60\u597d
    print(repr(unicode)) # '\\u4f60\\u597d'
    print(unicode_to_str('\\u4f60\\u597d')) # Hello

Python Unicode string and normal string conversion

Unicode is a character encoding standard designed to provide a unique numerical identification (called code point) for every character in all writing systems in the world.

Code point:

  • Each Unicode character is assigned a unique number, called a code point
  • Representation: u+ followed by 4-6 hexadecimal number (such as U+0041 means Latin capital letter A)

unicode is a coding standard for representing text, which allows processing and storing characters in multiple languages. In Python, if the printed content is u’xxx’, this usually means that the content is a unicode string.

So, how to convert a Unicode string to a normal string:

Method 1. Use str() function

unicode_str = u'hello world'
normal_str1 = str(unicode_str) #Use str() function to convert to normal stringprint(normal_str1)

Method 2. Use encode() function and decode() function for encoding and decoding

unicode_str = u'hello world'
normal_str2 = unicode_str.encode('utf-8')  # Use the encode() method to convert it into a normal string encoded by utf-8, and then use decode() to decode itprint(normal_str2)

Convert Unicode sequences to strings in Python3

Method 1: Use the `.encode()` method

def unicode_to_string(unicode_sequence):
    """
    WillUnicodeConvert sequence to string
    
    parameter:
        unicode_sequence (str): Unicodesequence
    
    return:
        str: Converted string
    """
    # Encode Unicode sequences to UTF-8 (default) or specified character set    return unicode_sequence.encode('utf-8').decode()

# Test casesif __name__ == "__main__":
    unicode_str = 'Hello World!  '
    encoded_str = unicode_to_string(unicode_str)
    print("Original Unicode string:", unicode_str)
    print("Converted string:", encoded_str)

Output example:

Original Unicode string: Hello, world!
Converted string: Hello, world!

Method 2: Use the `()` method

import json

def unicode_to_string(unicode_sequence):
    """
    WillUnicodeConvert sequence to string
    
    parameter:
        unicode_sequence (str): Unicodesequence
    
    return:
        str: Converted string
    """
    # Use method, it will automatically handle Unicode encoding issues    return (unicode_sequence)

​​​​​​​# Test casesif __name__ == "__main__":
    unicode_str = 'Hello World!  '
    encoded_str = unicode_to_string(unicode_str)
    print("Original Unicode string:", unicode_str)
    print("Converted string:", encoded_str)

Output example:

Original Unicode string: Hello, world!
Converted string: "Hello, world!"

Application scenarios of artificial intelligence big model

Suppose we have an AI model that requires inputting text data from different locales into the training stage. In this case, converting Unicode sequences to strings is crucial to ensuring uniformity and compatibility of the data. For example, the input to a Chinese translation model might be a Unicode sequence containing characters from multiple languages. With the above method, we can ensure that these Unicode sequences are correctly decoded into strings in UTF-8 encoded formats that can be trained.

Test cases

def test_unicode_to_string():
    assert unicode_to_string('Hello World!  ') == 'Hello World!  '
    assert unicode_to_string('Welcome to the world of Python 3!  ') == 'Welcome to the world of Python 3!  '
    assert unicode_to_string('This is a test case.  ') == 'This is a test case.  '

test_unicode_to_string()

Summarize

Python provides powerful and easy-to-use tools to handle Unicode strings. By understanding string types, common operations, and encoding and decoding methods, you can easily handle characters in various languages. Whether it is developing international applications or processing multilingual text, mastering these basic knowledge is very important.

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