In this article, we will share some of the different Python techniques and have fun with Python.

1. Print Prints colored information

You know the information printing function in Python, Print, and we usually use it to Print something as a simple debugging.

def esc(code=0) :return f'[{code}m'

print(esc('31; 1; 0 ') + 'Error:'+esc()+'important')
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After running this code on the console or Pycharm, you will get the result.

Error:important
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Error is underlined in red and important is the default color

The following parameters can be set:

Description: foreground background color -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --30                40black31                41red32                42green33                43yellow34                44blue35                45purple36                46Green, blue37                47Meaning of the white display -------------------------0Terminal Default Settings1The highlighted4Use underscores5flashing7The white shows8Invisible example: [1;31; 40m < ! --1- Highlight31- Foreground color red40- Background color black -- >Copy the code

2. Use timers in Python

Today, I saw a humanized schedule module. Currently, the star number is 6432, which is still very popular. This module also adheres to the principle of For Humans, which is recommended here. Address github.com/dbader/sche…

1. You can install it using PIP.

pip install schedule
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Use cases

import schedule
import time

def job():
    print("I'm working...")

schedule.every(10).minutes.do(job) 
schedule.every().hour.do(job)
schedule.every().day.at("At 10:30").do(job)
schedule.every().monday.do(job)
schedule.every().wednesday.at("Anyone").do(job)
schedule.every().minute.at(", 17").do(job)

while True:
    schedule.run_pending()
    time.sleep(1)
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From the literal meaning of the word, you know what it does. schedule.every().monday.do(job)

3. Implement a progress bar

from time import sleep

def progress(percent=0, width=30):
    left = width * percent / / 100
    right = width - left
    print('['.The '#' * left, ' ' * right, '] ',
          f' {percent:.0f}%',
          sep=' ', end=' ', flush=True)

for i in range(101):
    progress(i)
    sleep(0.1)
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Display effect

In the code above, print has several useful arguments. Sep is used as a separator, and the default is a space. This is set to empty to make each character more compact. Flush = False; flush = False; print to f; When flush = True, it immediately flushs and prints.

4. Gracefully print nested types of data

If you’re printing a JSON string or dictionary, there’s no hierarchy at all, and it’s all about the output format.

import json
my_mapping = {'a': 23.'b': 42.'c': 0xc0ffee}
print(json.dumps(my_mapping, indent=4, sort_keys=True))
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You can try printing my_mapping with print only.

import pprint
my_mapping = [{'a': 23.'b': 42.'c': 0xc0ffee}, {'a': 231.'b': 42.'c': 0xc0ffee}]
pprint.pprint(my_mapping,width=4)
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5. Simple classes are defined using Namedtuple and dataclass

Sometimes we want to implement a similar class function, but there is not that complex method to operate, this time can consider the following two methods.

from collections importPreviously simple classes could be implemented using namedtuple. Car = namedtuple('Car'.'color mileage')

my_car = Car('red'.3812.4)
print(my_car.color)
print(my_car)
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However, all attributes need to be defined in advance. For example, to use my_car.name, you need to change the code to look like this.

from collections importPreviously simple classes could be implemented using namedtuple. Car = namedtuple('Car'.'color mileage name')

my_car = Car('red'.3812.4."Auto")
print(my_car.color)
print(my_car.name)
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The disadvantages of using namedTuple are obvious.

So a better solution now is to add Dataclass to the standard library.

from dataclasses import dataclass
@dataclass
class Car:
    color: str
    mileage: float

my_car = Car('red'.3812.4)
print(my_car.color)
print(my_car)
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6. F – string! r,! a,! s

F-string appears in Python3.6 as the current best concatenated string form. Take a look at the structure of f-string

f ' < text> { < expression> < optional ! s, ! r, or ! a> < optional : format specifier> } < text> . '
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The ‘! S ‘calls STR () on the expression, ‘! R ‘calls repr () on the expression, ‘! A ‘calls ASCII () on expression

class Comedian:
    def __init__(self.first_name.last_name.age) :self.first_name = first_name
        self.last_name = last_name
        self.age = age

    def __str__(self):
        return f"{self.first_name} {self.last_name} is {self.age}."

    def __repr__(self):
        return f"{self.first_name} {self.last_name} is {self.age}. Surprise!"
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call

&gt; &gt; &gt; new_comedian = Comedian("Eric"."Idle"."74") &gt; &gt; &gt; f"{new_comedian}"
'Eric Idle is 74.'&gt; &gt; &gt; f"{new_comedian}"
'Eric Idle is 74.'&gt; &gt; &gt; f"{new_comedian! r}"
'Eric Idle is 74. Surprise! '
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(2)! A example of

&gt; &gt; &gt; a ='some string'&gt; &gt; &gt; f'{a! r}'
"'some string'"
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Is equivalent to

&gt; &gt; &gt; f'{repr(a)}'
"'some string'"
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(3)! An example of d

Similar to the 2

Pycon2019 someone put forward a prospect! Function realization of D:

7. Use of “=” in f-string

Python3.8 has such a feature

a = 5
print(f"{a=}")
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The result after printing is zero

a=5
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Isn’t it convenient that you don’t have to use f”a={a}” anymore?

The walrus operator := is used

a =6
if (b:=a+1)&gt;6:
   print(b)
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Assignment can be performed at the same time, similar to the Go language assignment.

b =7
if b&gt;6:
   print(b)
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How is not a lot of simple, but this function 3.8 start to use oh.

conclusion

That’s the end of today’s content, most of which is a fragment of knowledge recorded in my blog garden. Here I sort out and share with you. My blog park address :www.cnblogs.com/c-x-a/, interested in… Go so it’s going to record some go stuff as well.

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