刷题继续

昨天和大家分享了 21-30 题，今天继续来刷 31~40 题

Question 31:

Define a function which can print a dictionary where the keys are numbers between 1 and 20 (both included) and the values are square of keys.

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解法一

def printDict():
    d=dict()
    for i in range(1,21):
        d[i]=i**2
    print(d)    
printDict()

解法二

def printDict():
    dict={i:i**2 for i in range(1,21)}   
    print(dict)
printDict()

Question 32:

Define a function which can generate a dictionary where the keys are numbers between 1 and 20 (both included) and the values are square of keys. The function should just print the keys only.

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解法一

def printDict():
    dict = {i: i**2 for i in range(1, 21)}
    print(dict.keys())      
printDict()

解法二

def printDict():
    d=dict()
    for i in range(1,21):
        d[i]=i**2
    for k in d.keys():    
        print(k)
printDict()

Question 33:

Define a function which can generate and print a list where the values are square of numbers between 1 and 20 (both included).

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解法一

def printList():
    lst = [i ** 2 for i in range(1, 21)]
    print(lst)
printList()

Question 34:

Define a function which can generate a list where the values are square of numbers between 1 and 20 (both included). Then the function needs to print the first 5 elements in the list.

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解法一

def printList():
    lst = [i ** 2 for i in range(1, 21)]
    print(lst[:5])

printList()

Question 35:

Define a function which can generate a list where the values are square of numbers between 1 and 20 (both included). Then the function needs to print the last 5 elements in the list.

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解法一

def printList():
    lst = [i ** 2 for i in range(1, 21)]
    print(lst[-5:])
printList()

Question 36:

Define a function which can generate a list where the values are square of numbers between 1 and 20 (both included). Then the function needs to print all values except the first 5 elements in the list.

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解法一

def printList():
    lst = [i ** 2 for i in range(1, 21)]
    print(lst[5:])
    
printList()

Question 37:

Define a function which can generate and print a tuple where the value are square of numbers between 1 and 20 (both included).

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解法一

def printTuple():
    lst = [i ** 2 for i in range(1, 21)]
    print(tuple(lst))

printTuple()

Question 38:

With a given tuple (1,2,3,4,5,6,7,8,9,10), write a program to print the first half values in one line and the last half values in one line.

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解法一

tpl = (1,2,3,4,5,6,7,8,9,10)

for i in range(0,5):
    print(tpl[i],end = ' ')
print()
for i in range(5,10):
    print(tpl[i],end = ' ')
    

解法二

tp = tuple(i for i in range(1,11))
lst1,lst2 = list(tp[:5]),list(tp[5:])
print(lst1)
print(lst2)

Question 39:

Write a program to generate and print another tuple whose values are even numbers in the given tuple (1,2,3,4,5,6,7,8,9,10).

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解法一

tpl = (1,2,3,4,5,6,7,8,9,10)
tpl_even = tuple(i for i in tpl if i%2 == 0)
print(tpl_even)

解法二

tpl = (1,2,3,4,5,6,7,8,9,10)
tpl_even= tuple(filter(lambda x : x%2==0,tpl))  
print(tpl_even)

Question 40:

Write a program which accepts a string as input to print “Yes” if the string is “yes” or “YES” or “Yes”, otherwise print “No”.

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解法一

s = input()
if s.lower() == 'yes': 
    print('Yes')
else:
    print("No")

源代码下载

这十道题的代码在我的 github 上，如果大家想看一下每道题的输出结果，可以点击以下链接下载：

• Python 31-40 题

我的运行环境 Python 3.6+, 如果你用的是 Python 2.7 版本，绝大多数不同就体现在以下 3 点：

• raw_input() 在 Python3 中是 input()
• print 需要加括号
• fstring 可以换成.format(), 或者 %s，%d

谢谢大家，我们下期见！希望各位朋友不要吝啬，把每道题的更高效的解法写在评论里，我们一起进步！！！