python reserved word

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

>>> import keyword
>>> keyword.kwlist
['False', 'None', 'True', '__peg_parser__', 'and', 'as', 'assert', 'async', 'await', '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']
>>> 

python comments

Single-Line Comments

# This is a single line comment

multiline comment

'''
Python It is an interpretive language: this means that there is no compilation in the development process. be similar to PHP and Perl Language.
​
Python Is an interactive language: this means that you can Python Prompt >>> Execute the code directly after.
​
Python Is an object-oriented language: That means Python Support object-oriented style or code encapsulated in object programming technology.
'''

python indent

The most distinctive feature of python is that it uses indentation to represent code blocks without curly braces {}.

if True:
    print ("True")
else:
    print ("False")

If the indents are inconsistent, it will cause a running error

if True:
    print("True")
else:
    print("False")
  print("False")
​
# File "C:/**/**/***/***.py", line **
#  print("False")
                ^
# IndentationError: unindent does not match any outer indentation level

python multiline statement

If an expression / statement is very long, we can use ` ` to realize multi line statement and line feed display

total = val_1 + \
        val_2 + \
        val_3 - \
        val_4

Multiline statements in [], {}, or () do not require backslashes``

In the dictionary {}

num_dict = {
    'num_1': 1,
    'num_2': 2,
    'num_3': 3
}
# print ---- {'num_1': 1, 'num_2': 2, 'num_3': 3}

In the list []

num_list = [
    1, 2, 3, 4,
    5, 6, 7, 8,
    9, 10, 11
]
# print ---- [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]

In tuple ()

num_tuple = (
    1, 2, 3,
    4, 5, 6,
    7, 8, 9
)
# print ---- (1, 2, 3, 4, 5, 6, 7, 8, 9)

python displays multiple statements on the same line

Use semicolons between statements; division

print(num_dict); print(num_tuple); print(num_list)

python print output and output do not wrap

print('python print output')

The default output of print is newline. If you want to realize no newline, you need to add end = "" at the end of the variable:

print( 'Hello', end=" " )
print( 'python')

# Output ----- > > Hello python 

print( 'Hello', end="*" )
print( 'python')
# Output ----- > > Hello * ython 

python multiple statements form a code group

Indent the same set of statements to form a code block, which we call a code group.

For compound statements such as if, while, def and class, the first line starts with a keyword and ends with a colon (:), and one or more lines of code after this line form a code group.

We call the first line and the following code group a clause.

if val : 
   pass
elif val_2 : 
   pass 
else : 
   pass

python import and from... Import

In python, use import or from... Import to import the corresponding module.

Import the whole module in the format of import somemodule

Import a function from a module in the format from some module import somefunction

Import multiple functions from a module in the form of: from somemodule import firstfunc, secondfunc, thirdffunc

Import all functions in a module in the format from some module import*

Import sys module

import sys 
for i in sys.argv:    
	print (i) 
print ('\n python Path is', sys.path)

Import argv and path members of sys module

#  Import specific members
from sys import argv,path   

# Because the path member has been imported, you do not need to add sys path
print('path:', path) 

Python experience sharing

It's good to learn Python well, whether in employment or sideline, but to learn python, you still need to have a learning plan. Finally, let's share a full set of Python learning materials to help those who want to learn Python!

1, Python learning routes in all directions

All directions of Python is to sort out the common technical points of Python and form a summary of knowledge points in various fields. Its usefulness is that you can find corresponding learning resources according to the above knowledge points to ensure that you learn more comprehensively.

2, Learning software

If a worker wants to do well, he must sharpen his tools first. The commonly used development software for learning Python is here, which saves you a lot of time.

3, Getting started video

When we watch videos, we can't just move our eyes and brains without hands. The more scientific learning method is to use them after understanding. At this time, the hand training project is very suitable.

4, Actual combat cases

Optical theory is useless. We should learn to knock together and practice, so as to apply what we have learned to practice. At this time, we can make some practical cases to learn.

5, Interview materials

We must learn Python in order to find a high paying job. The following interview questions are the latest interview materials from front-line Internet manufacturers such as Ali, Tencent and byte, and Ali has given authoritative answers. After brushing this set of interview materials, I believe everyone can find a satisfactory job.

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