Python core Programming The answer to the second edition of the exercises

2-5

#写一个while循环, the output integral type is 0~10

A=0
While a<11:
Print a
A+=1

#写一个for循环重复以上操作

For I in range (11):
Print I

2-6

#条件判断, determine whether a number is positive or negative, or 0. Start with a fixed value, then modify your code to support user input values to determine

A=int (raw_input ("Please input a number:"))
#a =6
If a>0:
Print "This number is positive!"
Elif a<0:
Print "This number is negative!"
Else
Print "This number is zero!"

2-7

#从用户那里接受一个字符串输入, and then displays the string verbatim, using the For loop implementation

A=raw_input ("Please input a string:")
For I in A:
Print I

#同样再用while循环实现上述

A=raw_input ("Please input a string:")
I=0
While I<len (a):
Print A[i]
I+=1

2-8

#创建一个包含五个固定数值的列表或元祖, output their and then modify the code to accept user input values, using the while and for loops respectively

The simplest algorithm for #print (reduce (lambda x,y:x+y,range (1,5)))

#for循环:

A=input ("Please input a list or a tuple:")
#a =[1,2,3,4]
S=0
For I in range (Len (a)):
S+=a[i]
Print S

#while循环:

A=input ("Please input a list or a tuple:")
#a =[1,2,3,4]
I=0
S=0
While I<len (a):
S+=a[i]
I+=1
Print S

2-9 loops and operators, create a list or tuple with five fixed values, output their average

#for循环

a=[1,2,3]
S=0
For I in range (Len (a)):
S+=a[i]
Print float (S/len (a))

#while Cycle

A=input ("Please input a list or a tuple:")
I=0
S=0
While I<len (a):
S+=a[i]
I+=1
Print float (S/len (a))

2-10 user input with loop and conditional judgment, using the Raw_input () function to prompt the user for a number between 1 and 100, if the number of user input satisfies this condition, the display succeeds and exits, otherwise displays an error message and then prompts the user to enter a value again, knowing that the condition is met.

While 1:
A=int (raw_input ("Please input a number:"))
If 1<=a<=100:
Print "success!"
Break
Else
print "Input Error!plese input again!"
Continue

2-11

#写一个带文本菜单的程序, the menu items are as follows: (1) Take 5 numbers and (2) take the average of 5 numbers; (X) exit, the user makes a selection, then performs the corresponding function

Def Menu ():
print "1.get sum of five numbers"
Print "2.get average of five numbers"
Print "X.exit"

Def Sum ():
l=[1,2,3,4,5]
Sum=0
For I in L:
Sum+=i
I+=1
return sum
Def Ave ():
Sum=sum ()
Ave=float (SUM)/5
Return Ave
While True:
Menu ()
Choice=input ("Please choice One:")
If choice==1:
Sum=sum ()
Print "sum is%d"%sum
Elif choice==2:
Ave=ave ()
Print "average is%f"%ave
Elif choice== ' x ':
Break
Else
Print "Wrong choice,please choose again!"

2-15

#让用户输入3个数值并将分别将他们保存到3个不同的变量中, do not use a list or sorting algorithm
#从小到大
While True:
Num1=int (raw_input ("Please input NUM1:"))
Num2=int (raw_input ("Please input num2:"))
Num3=int (raw_input ("Please input num3:"))
If num1>num2:
Tmp=num1
Num1=num2
Num2=tmp
If num2>num3:
Tmp=num2
Num2=num3
Num3=tmp
If num1>num2:
Tmp=num1
Num1=num2
Num2=tmp
Print "from Min to Max is%d,%d,%d"% (NUM1,NUM2,NUM3)
#从大到小:
While True:
Num1=int (raw_input ("Please input NUM1:"))
Num2=int (raw_input ("Please input num2:"))
Num3=int (raw_input ("Please input num3:"))
If num1<num2:
Tmp=num1
Num1=num2
Num2=tmp
If num2<num3:
Tmp=num2
Num2=num3
Num3=tmp
If num1<num2:
Tmp=num1
Num1=num2
Num2=tmp
Print "from Max to Min is%d,%d,%d"% (NUM1,NUM2,NUM3)

Python core Programming The answer to the second edition of the exercises