Python循环经典案例（for、while两种方法实现）

注：请尽量自行在pycharm完成代码并执行结果！

1、打印十行十列 *

# 方法一：while循环
i = 1
while i <= 10:
	j = 1
	while j <= 10:
		print("*",end="")
		j += 1
	i += 1
	print()

# 方法二：for循环
for i in range(1,11):
	for j in range(1,11):
		print("*",end="")
	print()

2、打印十行十列 ★，隔列换色（☆）

# 方法一：while循环
i = 1
while i <= 10:
	j = 1
	while j <= 10:
		if j % 2 == 1:
			print("★",end="")
		else:
			print("☆",end="")
		j += 1
	i += 1
	print()

# 方法二：for循环
for i in range(1,11):
	for j in range(1,11):
		if j % 2 == 1:
			print("★",end="")
		else:
			print("☆",end="")
	print()

3、打印十行十列★，隔行换色

# 方法一：while循环
i = 1
while i <= 10:
	j = 1
	while j <= 10:
		if i % 2 == 1:
			print("★",end="")
		else:
			print("☆",end="")
		j += 1
	i += 1
	print()

# 方法二：for循环
for i in range(1,11):
	for j in range(1,11):
		if i % 2 == 1:
			print("★",end="")
		else:
			print("☆",end="")
		j += 1
	i += 1
	print()

4、99乘法表

效果图：

# 方法一：while循环
i = 1
while i <= 9:
	j = 1
	while j <= i:
		num = "%d*%d=%2d " %(i,j,i*j)
		print(num,end="")
		j += 1
	i += 1
	print()

# 方法二：for循环
for i in range(1,10):
	for j in range(1,i+1):
		num = "%d*%d=%2d " %(i,j,i*j)
		print(num,end="")
	print()

5、99乘法表（与题4上下对称）

效果图：

# 方法一：while循环
i = 9
while i >= 1:
	j = 1
	while j <= i:
		num = "%d*%d=%2d " %(i,j,i*j)
		print(num,end="")
		j += 1
	i -= 1
	print()

# 方法二：for循环
for i in range(9,0,-1):
	for j in range(1,i+1):
		num = "%d*%d=%2d " %(i,j,i*j)
		print(num,end="")
	print()

6、99乘法表（与题4左右对称）

效果图：

# 方法一：while循环
i = 1
while i <= 9:
	k = 9 - i
	while k > 0:
		print(7*" ",end="")
		k -= 1
	j = 1
	while j <= i:
		num = "%d*%d=%2d " %(i,j,i*j)
		print(num,end="")
		j += 1
	i += 1
	print()

# 方法二：for循环
for i in range(1,10):
	for k in range(9-i,0,-1):
		print(7*" ",end="")
	for j in range(1,i+1):
		num = "%d*%d=%2d " %(i,j,i*j)
		print(num,end="")
	print()		 

7、99乘法表（与题6上下对称）

效果图：

# 方法一：while循环
i = 9
while i >= 1:
	k = 9 - i
	while k > 0:
		print(7*" ",end="")
		k -= 1
	j = 1
	while j <= i:
		num = "%d*%d=%2d " %(i,j,i*j)
		print(num,end="")
		j += 1
	i -= 1
	print()
	
# 方法二：for循环
for i in range(9,0,-1):
	for k in range(9-i,0,-1):
		print(7*" ",end="")
	for j in range(1,i+1):
		num = "%d*%d=%2d " %(i,j,i*j)
		print(num,end="")
	print()		

8、求吉利数字100～999 （111、222…123、234…987、876…）

# 方法一：while循环,运算算法
i = 100
while i <= 999:
	bai = i // 100
	shi = i // 10 % 10
	ge = i % 10
	if bai == shi and shi == ge:
		print(i)
	elif bai+1 == shi and shi+1 == ge:
		print(i)
	elif bai-1 == shi and shi-1 == ge:
		print(i)
	i += 1

# 方法二：while循环,字符串算法
i = 100
while i <= 999:
	bai = i // 100
	shi = i // 10 % 10
	ge = i % 10
	strvar = str(i)
	if strvar[0] == strvar[1] and strvar[1] == strvar[-1]:
		print(i)
	elif bai+1 == shi and shi+1 == ge:
		print(i)
	elif  bai-1 == shi and shi-1 == ge:
		print(i)
	i += 1

# 方法三：for循环
for i in range(100,1000):
	bai = i // 100
	shi = i // 10 % 10
	ge = i % 10
	if bai == shi and shi == ge:
		print(i)
	elif bai+1 == shi and shi+1 == ge:
		print(i)
	elif bai-1 == shi and shi-1 == ge:
		print(i)

9、百钱买百鸡

公鸡 母鸡 小鸡
公鸡1块钱1只,母鸡3块钱一只,小鸡5毛钱一只
问: 用100块钱买100只鸡,有多少种买法?

# 方法一：while循环
count = 0
x = 0
while x <= 100:
	y = 0
	while y <= 33:
		z = 0
		while z <= 100:
			if x+y+z == 100 and x+3*y+0.5*z == 100:
				count += 1
			z += 1
		y += 1
	x += 1
print(count)

# 方法二：for循环
count = 0
for x in range(0,101):
	for y in range(0,34):
		for z in range(0,101):
			if x+y+z == 100 and x+3*y+0.5*z == 100:
				count += 1
print(count)