Python Introductory classic Python Programming practice oriented to solving computational problems Lesson2

5+3>9-2
Is that 8>7,python is first calculated and then compared
Other arithmetic operations are performed before the boolean operator

Python supports comparisons such as:
aint = 5
0<=aint<=5

while Booleanexpression:
#suite 1
#else:
#suite2
When the while loop Boolean expression is false, the Else statement is entered. Note: A while inside of a break out of the loop also skips the Else statement.

Exercise 2

1.

#-*-coding:gbk-*-
for I in Range (100,1000):
	if i%17==0:
		print I,

2.

#-coding:gbk-*-
# (a)
Mynum=int (raw_input ("Please input a number:")
sum=0 while
mynum>=1:
	Sum+=mynum
	mynum-=1
print Sum
# (b) for
I in range (1,mynum+1):
	sum=0
	kong=0 str=
	"" For
	J in Range (1,i+1):
		Sum+=j
		if j==i:
			str+=str (j) + "" * ((Mynum-kong) *2-1)
		else:
			Str+=str (j) + "+"
		kong+=1
	Print Str, "=", Sum
	print
# (c) for
I in range (1,mynum+1):
	sum=0
	kong=0
	str= ""
	for J in Range (1,i+1):
		sum+=j
		if j==i:
			str+=str (j) + "" * ((Mynum-kong) *2-1)
		else:
			Str+=str (j) + " + "
		kong+=1
	if sum%i==0:
		print Str," = ", Sum
		Print

3.

#-*-coding:gbk-*-
#method_1 from the back-forward output 
moneystr=raw_input ("Input your To convert (NAT):")
Money=int ( MONEYSTR)
If money/29!=0:
	if money%29!=0:
		print Money%29, "Nat",
	money=money/29
	if money/17!=0:
		if money%17!=0:
			print money%17, "tin",
		money=money/17
		print money, "gallon"
	else:
		print Money, "Tin Can"
else:
	if money!=0:
		print Money, "Nat"
#method_2
x=int (moneystr)
if x/(29* !=0: #money数是否大于或等于29 *17 integer times, there are gallons of
	print x/(29*17), "gallons",
	x=x% (29*17) #得到加仑后的余数

if x/29!=0:# Whether the money number is greater than or equal to 29 integer times, there are tin
	print x/29, "tin", #输出锡可
	if x%29!=0: #有锡可后的余数
		print X%29, "Nat"
else:# Money not enough a tin can, not zero output NAT
	if x!=0:
		print x, "Nat"

4.

#-*-coding:gbk-*-
#当因数加到一半就大于输入的数字, break
#SumofDivisor预先就设为1, divisor is 2, less one step
#更多详情请参考 "Mason Prime number"
Topnum=int (raw_input ("Please input the upper limit:") thenum=2 deficient=0 abundant=0 while
thenum <=topnum:
	#print thenum
	divisor=2
	sumofdivisor=1 while
	divisor<thenum: #不包括数字本身
		if Thenum%divisor==0:
			sumofdivisor+=divisor
		if sumofdivisor>thenum:
			break
		divisor+=1
	If Sumofdivisor==thenum:
		print thenum,
	elif sumofdivisor>thenum:
		abundant+=1
	Else:
		Deficient+=1
	thenum+=1
print
print abundant, "are abundant."
Print deficient, "are deficient."

5.

#-*-coding:gbk-*-
h=raw_input ("Please input your height (m):")
w=raw_input ("Please input your weight (kg):")
h=float (h)
W=float (w)
bmi=w/h**2
print "Your BMI is", BMI
if bmi>=30.0:
	print Too Fat "
elif 25.0<=bmi<=29.9:
	print" overweight "
elif 18.5<bmi<=24.9:
	print" Normal "
elif bmi<=18.5:
	print "Too Light"

6.

#-*-coding:gbk-*-
int=raw_input ("Input an Integer:") While not
Int.isdigit ():
	int=raw_input ("Error:try Again. Input an integer: "
int=int (int)
print" "The" ", int

7.

#-*-coding:gbk-*-
#1) for
I in range (1,10):
	str= "' for J-in
	Range (1,i+1):
		str+=str (j)
	# Print str
	print str, "*", 8, "+", I, "=", int (Str) *8+i
#2) for
I in range (1,10):
	str= "" for
	J in Range (1,i+1):
		str+=str (j)
	#print str
	print str, "*", 9, "+", i+1, "=", int (STR) *9+ (i+1)
#3)
For I in Range (9,1,-1):
	str= ""
	for J in Range (9,i-1,-1):
		str+=str (j)
	#print str
	print str, "*" , 9, "+", i-2, "=", int (STR) *9+ (i-2)
#4) for
I in range (1,10):
	str= "" for
	J in Range (1,i+1):
		str +=STR (1)
	#print str
	print str, "*", str, "=", int (str) **2

8.

#-*-coding:gbk-*-
Import Math

mynum=int (raw_input ("Please input a number:")
i=2 while
i<= Math.sqrt (myNum):
	if mynum%i==0:
		print MyNum, "is not a prime." 
		Break
	i+=1
else:
	print MyNum, ' is a prime. '

9.

#-*-coding:gbk-*-
topnum=raw_input ("Upper limit:")
Topnum=int (topnum) for
thenum in range (2,topnum+ 1):
	sumofdivisors=0 for
	divisor in range (1,thenum):
		if thenum%divisor==0:
			sumofdivisors+= Divisor
		if Sumofdivisors>thenum:
			break
	if thenum==sumofdivisors:
		print Thenum, ' is perfect. '
	Elif thenum<sumofdivisors:
		print Thenum, "is abundant."
	else:
		print Thenum, "is deficient."

10.

#-*-coding:gbk-*-
Import Math
# (a) # (b)
expr= "Ax^2+bx+c"
print Expr
a=float (Raw_input ("A:")
b=float (Raw_input ("B:"))
C=float (Raw_input ("C:"))
delta=b**2-4*a*c
if delta==0:
	res= (-b+ MATH.SQRT (Delta))/(2*a)
	print Expr, "has one root."
	Print "It is", res
elif delta>0:
	res1= (-b+math.sqrt (Delta))/(2*a)
	res2= (-b-math.sqrt (Delta))/(2* A)
	print Expr, "has two roots."
	Print "They are", Res1,res2
Else:
	part1=math.sqrt (Math.fabs (delta))
	Part2=-math.sqrt (Math.fabs ( Delta))
	x=-b/2*a
	y=part1/2*a
	res1=x+eval (str (y) + "J")
	Res2=x-eval (str (y) + "J")
	Print EXPR, "has two imaginary roots."
	Print "They are", res1,res2

11.

(a)
is odd but its cubic is not 27--1
is odd and its cubic is 27--3
is even but is less than equal to 10--2
is even but greater than 10--12
myvar=1,3,2,12
(b)
{x|x =2*i+1} (i is an arbitrary integer other than 1, i!=1)
{3}
{x|x=2*i} (i is any integer less than or equal to 5, i<=5)
{x|x=2*i} (i is any integer greater than 5, i>5)

12.

#-*-coding:gbk-*-
str=raw_input ("Input a string:")
s= "for
I in range (len (STR)):
    if (i+1)%3==0:s+= Str[i]
print S

13. Slightly

14.is See id, = = See value

15. Insert "I-=1" between row 6th and line 7th, otherwise the dead loop

16. Inserting if...break inside a while loop

17.

#-*-coding:gbk-*-
Import Math
#初级版
#Num =raw_input ("Enter an integer greater than 2:")
#while Num.isdigit ():
#    Num=raw_input ("Error.") It is isn't an interger. Try again: ")
#Num =int (Num)
#while num<=2:
#    Num=raw_input (" Error. Integer should be greater than 2. Try again: ")
#i =0
#while num>=2:
#    num=math.sqrt (Num)
#    i+=1
#    Print ( "%d:%.3f"% (i,num))

#高级版
#用函数什么的最方便了 =. =
def ifinputvalid (x):
    try:
        if int (x) >2: return
            x
        else:
            print "Integer less than 2!" Return
            0
            
    except:
        print "isn't an integer!!!"
        return 0

num=raw_input ("Enter a integer greater than 2:") While not
Ifinputvalid (Num):
    num=raw_input (" Enter an integer greater than 2: ")
num=int (num)
i=0 while
num>=2:
    num=math.sqrt (num)
    i+= 1
    print ("%d:%.3f"% (i,num))

18. Slightly

(c)

20. Slightly

21.True; False

22. Iterators are a way to access elements within a collection. The iterator object is accessed from the first element of the collection until all the elements have been accessed once and end. e.g. range (); It=iter (LST), It.nest ()

23.continue ignore the statement after the loop, jump directly to the next loop; break, jump straight out of the loop body

24.

#-*-coding:gbk-*-
#检查一个数是否是回文数
def ifpalindrome (x):
    l=len (x)
    ok=1 for-
    i in range (int (L/2.)):
        if x[i]!=x[l-i-1]:
            ok=0 break return
    OK

x=10000 while
x<999999:
    if Ifpalindrome ( STR (x) [-4:]):
        num=x
        y=x+1
        if Ifpalindrome (str (y) [-5:]):
            more=2 while
            more<=10:
                Z=y+more
                if Ifpalindrome (str (z) [1:-1]):
                    break
                more+=1
                #print "Add" and more
            k=z+3
            if Len (str (k)) ==6:
                if Ifpalindrome (str (k)):
                    print Num,more
    x+=1

The actual number of miles to go when #后面的数字指的是 "over 3 miles"

25.

#-*-coding:gbk-*-for
num2 in range (10,100):
    num3=num2**2
    if 100<=num3<1000 and str (num3) [ -2:]== STR (num2):
        print num2

Results: 625

26.

#-*-coding:gbk-*-
s,e,n,d,m,o,r,y=1,0,0,0,1,0,0,0 for
S in range (1,10):
    s=s to E in
    range (0,10):
        e=e
        for N in range (0,10):
            n=n
            to D in range (0,10):
                D=d
                m=1# logical Inference M must be 1 for
                o in range (0,10) :
                    o=o for
                    R in range (0,10):
                        r=r to Y in
                        range (0,10):
                            y=y
                            #print s,e,n,d,m,o,r,y
                            Send=int (str (S) +str (e) +str (N) +str (D))
                            more=int (str (m) +str (o) +str (R) +str (e)) Money=int (str (
                            m) +str (o) + STR (N) +str (E) +str (Y))
                            if Send+more==money and Len (set ([S,e,n,d,m,o,r,y])) ==8:
                                print Send, "+", more, "=", Money

Results: 9567 +1085 =10652

Programming topics are later updated ... To be Continued ...