循环练习:
1.随机输入5个数,输出最大值和最小值:
num = 1 # 定义随机变量num 是输入的个数
while num <= 5:
a = int(input('请输入第{}个数:'.format(num))) # 将输入的数转化为整数型
if num == 1: # 输入第一个数时最大值最小值都是这个数
max = a
min = a
else:
if a > max:
max = a
elif a < min:
min = a
num += 1
print('最大值max是:{},最小值min是{}:'.format(max, min)
2.用while和for循环打印九九乘法表:
while:
row = 1 # 行
while row<=9:
col = 1 # 列
while col<=row:
print(col,'*',row,'=',col*row,end='\t')
col+=1
print()
row+=1
for :
for row in range(1,10):
for col in range(1,row+1):
print(col,'*',row,'=',col*row,end='\t')
print()
3.判断字符串中字母,数字,下划线的个数。
s = 's3j_d67h_a5s624b_u'
方法一:
s = 's3j_d67h_a5s624b_u'
count1 = 0 # 定义字母个数
count2 = 0 # 定义数字个数
count3 = 0 # 定义下划线个数
for i in s:
if i >='a'and i<='z'or i >= 'A'and i <='Z':
count1+=1
elif i >='1' and i<= '9 ':
count2+=1
else:
count3+=1
print('字母为{}个,数字为{}个,下划线为{}个'.format(count1,count2,count))
方法二:
s = 's3j_d67h_a5s624b_u'
count1 = 0
count2 = 0
count3 = 0
for i in s: # 遍历字符串s
if i.isalpha(): # 判断是否是字母组成
count1 += 1
elif i.isdigit(): # 判断是否是数字组成
count2 += 1
else: # 其余为下划线
count3 += 1
print('字母为{}个,数字为{}个,下划线为{}个'.format(count1, count2, count3))