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# pta python lab

## 汪汪队，熬大夜

### 1.

``````str1 = input()
str2 = ""
if str1=='':
print('NULL')
else:
for v in str1:
# F-Z 直接减小5
if 'Z' >= v >= 'F':
str2 += (chr(ord(v) - 5))
# A-E 减小5位之后的ascii码不是字母，所以添加26位减5=加21
elif 'E' >= v >= 'A':
str2 += (chr(ord(v) + 21))
#其他的原样输出
else:
str2 += str(v)
print(str2)
``````

### 2.

``````x=float(input())
if x<3:
# format(x,'.2f') 保留两位小数
print('f('+str(format(x,'.2f'))+')=1.20')
elif 3==x:
print('f('+str(format(x,'.2f'))+')=10.00')
else:
print('f('+str(format(x,'.2f'))+')='+str(2*x+1))
``````

### 3.

``````import math
r=float(input())
print(format(math.pi*r*r,'.2f'))
``````

### 4.

``````num1 = input()
num2 = input()
sum = ''

#算出最长字符串长度
if len(num1) < len(num2):
maxLen = len(num2)
else:
maxLen = len(num1)

# 将两个字符串反转，便于计算
num1 = ''.join(reversed(num1))
num2 = ''.join(reversed(num2))

# 用t统计是否进位
t = 0
# 123
# 789
for i in range(maxLen):
# tmp记录同位相加结果

# 如果num1和num2都没被读取完全
if len(num1) > i and len(num2) > i:
tmp = int(num1[i]) + int(num2[i]) + t
# 如果num2被读完了
elif len(num1) > i:
tmp = int(num1[i]) + t
# 如果num1被读完了
elif len(num2) > i:
tmp = int(num2[i]) + t

# 用t统计是否进位
t = int(tmp / 10)
# sum追加个位部分
sum += str(tmp % 10)

#如果最后余数为1,加上
if 1==t:
sum+='1'
#将结果反转
print(''.join(reversed(sum)))
# 相同位置运算结束,计算不同位
#       123
# 45    678

``````

### 5.

``````x=input().split(' ')

money=float(x[0])
year=int(x[1])
rate=float(x[2])

print('interest='+format(money*(1+rate)**year-money,'.2f'))
``````

### 6.

``````x=int(input())
if 0==x%2:
print(str(x)+'是偶数')
else:
print(str(x)+'不是偶数')
``````

### 7.

``````i=1
while i > 0:
i+=1
if 1==i%5:
if 5==i%6:
if 4==i%7:
if 10==i%11:
print(i)
break
``````

### 8.

``````x=input()
print('hello,'+x)
``````

### 9.

``````x=0

#总人数
total_count=0
#没及格人数
count=0
#总分
sum=0
while x>=0:
x=int(input())
if x>0:
sum+=x
total_count+=1
if x<60:
count+=1
if total_count!=0:
print('平均分='+format(sum/total_count,'.2f')+',不及格人数='+str(count))
else:
print('没有学生')

``````

### 10.

``````str=input()
x=int(input())
y=int(input())

if x<1 or y>len(str)+1 or x>=y:
print('没子串！')
else:
print(str[x-1:y])
``````

### 11.

``````str1=input()
x=input()
count=1

#b记录是否找到
b=True

for v in str1:
if v==x:
print('index='+str(count))
b=False
break

count+=1
if b :
print("can't find letter",x)

``````

### 12.(不完整)

``````s=input().split(' ')

if str.isdigit(s[0]) and str.isdigit(s[1]):
x=int(s[0])
y=int(s[1])
if x<0 or y<0:
print('不能负数')
else:
#p,q 分子,分母
p=1
q=1

for i in range(0,x):
p*=(y-i)

for i in range(1,x+1):
q*=i

print('result='+format(p/q,'.2f'))
else:
print('请输入数值')
``````

### 13.

``````x = int(input())

if 2 == x:
print(str(x), 'is prime')
elif x < 2:
print(str(x), 'is not prime')
else:
b = True
for i in range(2, x):
if x % i == 0:
print(str(x), 'is not prime')
b = False
break

if b:
print(str(x), 'is prime')
``````

### 14.(未完成)

``````x=input().split(' ')
s=''

for v in x:
f=float(v)
if f<5000:
s+=str(f*15)
else:
s+=str(f)
s+=' '

print(s.split(' '))
``````

### 15.(未完成)

``````
``````

### 16.

``````import math
#创建判断是否为数字的函数，如果是，则返回true
def is_number(s):
try:
float(s)
return True
except ValueError:
pass

x=input()

if is_number(x):
n=float(x)
if n>0:
print('f('+str(format(n,'.2f'))+') =',format(math.cos(n)+math.e**n,'.2f'))
else:
print('f('+str(format(n,'.2f'))+') = 0.00')

else:print('Input Error')
``````

### 17.

``````import math

def is_number(s):
try:
float(s)
return True
except ValueError:
pass

x=input()

if is_number(x):
n=float(x)
if n>0:
print('f('+str(format(n,'.2f')+') = '+format(math.log(n,math.e)+math.pow(n,0.5),'.2f')))
else:
print('f('+str(format(n,'.2f')+') = 0.00'))
else:
print('Input Error')
``````

### 18.

``````#创建字典m
m={}

while True:
s=input()
#如果输入为回车，则退出
if s=='':
break
else:
kv=s.split(':')
m[kv[0]]=kv[1]

course=input('请输入要查询的课程：n')

#获取课程分数
if None==m.get(course):
print('没有该门课程')
else:
print(m.get(course))
``````

### 19.

``````s=input().split(',')
x=int(s[0])
y=int(s[1])

if x<60 or y<60:
print('不合格')
elif (x+y)/2>=90:
print('成绩优秀')
else:
print('通过')
``````

### 20.(未完成)

``````
``````

### 21.

``````print('Life is short,I want to learn python!')
``````

### 22.

``````s=input()
x=int(input())

for i in range(0,x):
print(s,end='! ')
``````

### 23.

``````x=input()

if 'a'<=x<='z':
print(chr(ord(x)-32))
else:
print(x)
``````

### 24.

``````Ctrl + c
Ctrl + v
``````

### 25.

``````s=input()
l=len(s)-1
b=True

for i in range(0,int(l/2)+1):
if s[i]!=s[l-i]:
print('no')
b=False
break

if b :
print('yes')
``````

### 26.(未完成)

``````import random

x=random.randint(0,100)
#是否猜中
no_guess=True

for i in range(0,8):
n=int(input())
if n>x:
print('Too big')
elif n<x:
print('Too small')
else:
print('Luck You!')
no_guess=False
break

if no_guess:
print('Game Over!')
``````

### 27.

``````print('我要学Python')
``````

### 28.

``````x=input().replace(' ','').replace('[','').replace(']','').replace(''','').split(',')
s=''
for v in x:
s+=v+'_'
s=s[:-1]
print(s)

``````

### 29.

``````x=input()

print(x+'同学,人生苦短,我学python')
print(x[0]+'大侠,学好python,走遍天下也不怕')
print(x[1:]+'小朋友,学好python,你最帅')
``````