[ Python 常見問題 ] Text Progress Bar in the Console

Source From Here 
Question 
As title. How to draw a progress bar for long time execution task in command line mode? 

How-To 
For a hand-made version: 

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1. # Print iterations progress  
2. def printProgressBar (iteration, total, prefix = '', suffix = '', decimals = 1, length = 100, fill = '█'):  
3.     """  
4.     Call in a loop to create terminal progress bar  
5.     @params:  
6.         iteration   - Required  : current iteration (Int)  
7.         total       - Required  : total iterations (Int)  
8.         prefix      - Optional  : prefix string (Str)  
9.         suffix      - Optional  : suffix string (Str)  
10.         decimals    - Optional  : positive number of decimals in percent complete (Int)  
11.         length      - Optional  : character length of bar (Int)  
12.         fill        - Optional  : bar fill character (Str)  
13.     """  
14.     percent = ("{0:." + str(decimals) + "f}").format(100 * (iteration / float(total)))  
15.     filledLength = int(length * iteration // total)  
16.     bar = fill * filledLength + '-' * (length - filledLength)  
17.     print('\r%s |%s| %s%% %s' % (prefix, bar, percent, suffix), end = '\r')  
18.     # Print New Line on Complete  
19.     if iteration == total:   
20.         print()  
21.   
22. #   
23. # Sample Usage  
24. #   
25.   
26. from time import sleep  
27.   
28. # A List of Items  
29. items = list(range(0, 57))  
30. l = len(items)  
31.   
32. # Initial call to print 0% progress  
33. printProgressBar(0, l, prefix = 'Progress:', suffix = 'Complete', length = 50)  
34. for i, item in enumerate(items):  
35.     # Do stuff...  
36.     sleep(0.1)  
37.     # Update Progress Bar  
38.     printProgressBar(i + 1, l, prefix = 'Progress:', suffix = 'Complete', length = 50)  

For a exist python package tqdm: add a progress meter to your loops in a second: 

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1. >>> import time  
2. >>> from tqdm import tqdm  
3. >>> for i in tqdm(range(100)):  
4. ...     time.sleep(1)  
5. ...  
6. 27%|██████████████████████████████████                                                                                            | 27/100 [00:36<01:18,  1.08s/it]  

[ Python 常見問題 ] Is there a simple process-based parallel map for python?

Source From Here 
Question 
I'm looking for a simple process-based parallel map for python. With native support map function, the performance: 

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1. In [1]: data = range(10000000)  
2.   
3. In [2]: time alist = list(map(lambda e:(e*5+1)/2, data))  
4. CPU times: user 1.48 s, sys: 47.6 ms, total: 1.53 s  
5. Wall time: 1.53 s  
6.   
7. In [3]: time olist = [(e*5+1)/2 for e in data]  
8. CPU times: user 862 ms, sys: 54 ms, total: 916 ms  
9. Wall time: 917 ms  

How-To 
I seems like what you need is the map method in multiprocessing.Pool(): 

map(func, iterable[, chunksize])

A parallel equivalent of the map() built-in function (it supports only one iterable argument though). It blocks till the result is ready. This method chops the iterable into a number of chunks which it submits to the process pool as separate tasks. The (approximate) size of these chunks can be specified by setting chunksize to a positive integer

Below is the sample code to show the usage: 
- test.py 

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1. #!/usr/bin/env python3  
2. import multiprocessing  
3. from datetime import datetime  
4.   
5. def f(e):  
6.     return (e*5+1)/2  
7.   
8. data = range(10000000)  
9. pool = multiprocessing.Pool()  
10. st = datetime.now()  
11. print("Start at {}".format(st))  
12. mlist = pool.map(f, data)  
13. diff = datetime.now() - st  
14. print("Done with {} ms".format(diff.microseconds/1000))  

Execution result: 

$ ./test.py
Start at 2018-12-25 22:11:46.570080
Done with 245.617 ms

Supplement 
* Python 文章收集 - multiprocessing 模塊介紹

[ Python 常見問題 ] Currying decorator in python

Source From Here 
Question 
I am trying to write a currying decorator as @curry in python so the function can be: 

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1. @curry  
2. def myfun(a,b,c):  
3.     print("{}-{}-{}".format(a,b,c))  
4.       
5. myfun(1, 2, 3)  
6. myfun(1, 2)(3)  
7. myfun(1)(2)(3)   

How-To 
If you are using Python2: 

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1. def curry(x, argc=None):  
2.     if argc is None:  
3.         argc = x.func_code.co_argcount  
4.     def p(*a):  
5.         if len(a) == argc:  
6.             return x(*a)  
7.         def q(*b):  
8.             return x(*(a + b))  
9.         return curry(q, argc - len(a))  
10.     return p  
11.   
12. @curry  
13. def myfun(a,b,c):  
14.     print '%d-%d-%d' % (a,b,c)  

In Python3: 

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1. from inspect import signature  
2.   
3. def curry(x, argc=None):  
4.     if argc is None:  
5.         argc = len(signature(x).parameters)  
6.           
7.     def p(*a):  
8.         if len(a) == argc:  
9.             return x(*a)  
10.         def q(*b):  
11.             return x(*(a + b))  
12.         return curry(q, argc - len(a))  
13.     return p  
14.   
15. @curry  
16. def myfun(a,b,c):  
17.     print("{}-{}-{}".format(a,b,c))  
18.       
19. myfun(1, 2, 3)  
20. myfun(1, 2)(3)  
21. myfun(1)(2)(3)  

Output: 

1-2-3
1-2-3
1-2-3

Supplement 
* How can I find the number of arguments of a Python function?