Python exercises (a)

1. Print prime numbers between 100 and 200

for item in range(100,200):
    su_shu=True
    for i in range(2,item):
        if item % i ==0:
            su_shu = False
            break
    if su_shu==True:
        print(item,end='\t')

2. The output of the multiplication tables

for _list in range(9):
    for _col in range(_list+1):
        print(_col+1,'*',_list+1,'=',(_col+1)*(_list+1),end='\t')
    print()

3. The judge in 1000 - a leap year between 2000

year=1000
while year<2000:
    if (year%4==0 and year%100!=0) or year%400==0:
        print(year,end='\t')
    year+=1

4. Given the two values ​​of integer variables, the contents of the two values ​​to be exchanged.

a=10
b=20
a,b=b,a
print(a,b)

5. a text file, each line is a word. There may be repeated. Number of statistics for each word appears.

Example file:
aaa
bbb
ccc
aaa
bb
c
aaa

f=open('./test.txt','r')#python语言中一切接对象,print(type(f))可以看对象类型
word={}
for a in f:
    a = a.strip()#strip字符串前后的空格抠掉
    if a in word:
        word[a]+=1
    else:
        word[a]=1
print(word)
f.close()

6. selecting the maximum value of 10 integers.

a=[98,25,35,56,46,51,12,65,85,66]
max=a[0]
for item in a:
    if item>max:
        max=item
print(max)

98

7. The bubble sort in descending output

a=[98,25,35,56,46,51,12,65,85,66]
#冒泡排序
for counts in range(0,len(a)-1):
    sort=True
    for i in range(0,len(a)-1-counts):
        if a[i]<a[i+1]:
            a[i],a[i+1]=a[i+1],a[i]
            sort=False
    if sort==True:
        break
print(a)

8. Enter two digits input, and two numbers

a=input('请输入第一个数：')
b=input('请输入第二个数')
a=int(a)
b=int(b)
print('a+b=',a+b)

9. Create a list contains five values, each value is determined by user input, and calculates the average of five values.

a=[]
for count in range(5):
    x=input('你输入的第%d个数为>>' % (count+1))
    x=int(x)
    a.append(x)
print(a)
print((a[0]+a[1]+a[2]+a[3]+a[4])/5)

10. Calculate 1 / 1-1 / 2 + 1 / 3-1 / 4 + 1 / + 5 ...... 1/99 - 1/100 of the value.

ret=0
for item in range(1,101):
    ret+=((-1)**(item+1))*(1/item)
print(ret)