Python is designed to be very readable. Compared with other languages, English keywords are often used, and some punctuation marks in other languages ​​have a more distinctive grammatical structure than other languages.

coding

By default, Python 3 source code files are encoded in UTF-8, and all strings are unicode strings. Of course, you can also specify a different encoding for the source file:

# -*- coding: cp-1252 -*-

The above definition allows the use of character codes in the Windows-1252 character set in the source files, and the corresponding suitable languages ​​are Bulgarian, Belarusian, Macedonian, Russian, and Serbian.

Identifier

The first character must be a letter in the alphabet or an underscore _.

The other parts of the identifier consist of letters, numbers, and underscores.

Identifiers are case sensitive.

In Python 3, Chinese can be used as variable names, and non-ASCII identifiers are also allowed.

Python reserved words

Reserved words are keywords, and we cannot use them as any identifier names. Python's standard library provides a keyword module that can output all keywords of the current version:

>>> import keyword

>>> keyword.kwlist

['False','None','True','and','as','assert','break','class','continue','def','del','elif', ' else','except','finally','for','from','global','if','import','in','is','lambda','nonlocal','not' ,'or','pass','raise','return','try','while','with','yield']

Annotation

Single-line comments in Python begin with #, examples are as follows:

Examples (Python 3.0+)

#!/usr/bin/python3

# First comment

print ("Hello, Python!") # 2.comment

Execute the above code, the output result is:

Hello, Python!

Multi-line comments can use multiple # signs, as well as''' and """:

Examples (Python 3.0+)

#!/usr/bin/python3

# First comment

# 2.comment

'''

Third note

Fourth note

'''

"""

Fifth note

Sixth note

"""

print ("Hello, Python!")

Execute the above code, the output result is:

Hello, Python!