Python interview one hundred questions - comprehensive title (2)

table of Contents

1. Shallow copy (copy) and a deep copy (DeepCopy)
2. Write a generator, a two-dimensional list will be converted into a one-dimensional list
3. Please write a recursive generator, arbitrary multidimensional lists into one-dimensional list
4. How to get the current date and the date of each day of the year
5. Communication between processes
6. How to pass parameters to a thread function
7. How to create and use global objects in a thread
8. Do you know coroutine

0.1 shallow copy (copy) and a deep copy (DeepCopy)

'''
copy：只复制深层对象的引用
deepcopy：复制深层对象的本身
'''
import copy

a = [1, 2, 3, 4, ['a', 'b']]

c = copy.copy(a)    # 浅拷贝
d = copy.deepcopy(a)    # 深拷贝

a.append(5) # 在顶层，无论浅还是深，顶层都完全复制
print(c)	# [1, 2, 3, 4, ['a', 'b']]
print(d)	# [1, 2, 3, 4, ['a', 'b']]

a[4][0] = 'x'
print(a)	# [1, 2, 3, 4, ['x', 'b'], 5]
print(d)	# [1, 2, 3, 4, ['a', 'b']]

to sum up

0.2 preparation of a generator, the list into a two-dimensional one-dimensional list

'''
生成器：yield
'''
def myGenerator():
    numlist = [1, 2, 3, 4 , 5, 6, 7]
    for num in numlist:
        yield num

for num in myGenerator():
    print(num, end=' ')	# 1 2 3 4 5 6 7 

[[1, 2, 3], [2, 3, 4]] ---> [1. 2. 3. 2. 3. 4]
def enumList(nestedList):
    for subList in nestedList:
        for element in subList:
            yield element

nestedList = [[1, 2, 3], [2, 3, 4]]
for num in enumList(nestedList):
    print(num, end=' ')	
1 2 3 2 3 4 

to sum up

0.3 Please write a recursive generator, arbitrary multidimensional lists into one-dimensional list

def enumList(nestedList):
    try:
        for subList in nestedList:
            for element in enumList(subList):
                yield element
    except TypeError:
        yield nestedList    # 迭代单个值

nestedList = [4, [1, 2, 3], [2, 3, 4, [1, [2, 5], [2, 3], 5], 6]]
for num in enumList(nestedList):
    print(num, end=' ')
4 1 2 3 2 3 4 1 2 5 2 3 5 6    

to sum up

0.4 How to get the current date and the date of the first few days of the year, respectively,

import time

localtime = time.localtime(time.time())

print(localtime.tm_year)	# 2020
print(localtime.tm_mon)		# 2
print(localtime.tm_mday)	# 29（这个月第29天）
print(localtime.tm_hour)	# 21
print(localtime.tm_yday)	# 60（今年第60天）

to sum up

0.5 Communication between processes

.join () wait, do not write .join () performs the following immediate

0.6 How to pass parameters to a thread function

to sum up

0.7 How to create and use global objects in a thread

The global variable only for the current thread can not be shared among multiple threads

summary

0.8 You understand it coroutine

A topic

title two
1.run

2.create_task

summary