练习题（元组、列表、字符串）讲解总结

#1.元组元素求和b=(1,2,3,4,5,6,7,8,9)

# b = (1, 2, 3, 4, 5, 6, 7, 8, 9)
# total = 0
# for i in b:
#     # print(i)
#     total += i
#
# print(total)

2.输出元组内7的倍数及个位为7的数

b = (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
for i in b:
    if i % 7 == 0 or i % 10 == 7:
        print(i)

3.列表倒数
a=[123,4567,12,3456]
输出 a = [321, 7654, 21, 6543]

 第一种方法：
a = [123, 4567, 12, 3456]
for i in a:
    temp = 0
    while i > 0:
        # 第一次 0 +3 == 3  第二次 30+2 = 32  第三次 320+1 =321
        temp = temp * 10 + i % 10
        i = i // 10  # 12  1  0

    print(temp)
# 第二种方式：
a = [123, 4567, 12, 3456]
b = []
for i in a:
    i = str(i)  # 将int值转换成字符串类型的值
    # print(type(i))
    # print(i)
    i = i[::-1]
    print(i)
    i = int(i)
    print(type(i))
    b.append(i)

print(b)

1.‘2018-11-12’去掉‘-’输出

# s = '2018-11-12'
# s2 = s.replace('-', '')
# print(s2)

#2.统计字符串a中 1的个数 a=‘201811’

# a = '201811'
# ret = a.count('1')
# print(ret)

3.字符串换行输出a = '12345678901234567890’效果如下:

# 1234
# 5678
# 9012
# 3456
# 7890
# a = '12345678901234567890'
# b = 0
# for i in a:
#     print(i, end='')
#     b += 1
#     if b % 4 == 0:
#         print()

# for index, value in enumerate(a, start=1):
#     # print(index, value)
#     print(value, end='')
#     if index % 4 == 0:
#         print()

#4.字符串换行输出 a = ‘12345678901234567890’，效果如下:

# 1
# 23
# 456
# 7890
# 12345
# 67890

# a = '12345678901234567890'
#
# line = 1
# temp = 1
# for i in a:
#     print(i, end='')
#     if line == temp: # 2==1
#         line += 1 # 2 3
#         temp = 0 # 0 0
#         print() # 换行
#     temp += 1 # 1 2

# a = '12345678901234567890'
# x = 0
# y = 1
# c = 0
# while x <= len(a):
#     b = a[x:y]  # a[0:1]->1     b= a[1:3] -->2,3 b=[3:6]
#     x = y  # x=1    x=3
#     y += 2 + c  # y= y+2+c->3 # y =6
#     c += 1  # c=c+1 -->1 #  c=2
#     print(b)

5.统计数字，字母，下划线个数

# a = '1234abcABCDE_'
#
# num = 0  # 记录数字的个数
# char = 0  # 记录字符的个数
# xhx = 0  # 记录下划线的个数

# for i in a:
#     if i >= '0' and i <= '9':
#         '''判断是否是数字'''
#         num += 1
#     elif (i >= 'A' and i <= 'Z') or (i >= 'a' and i <= 'z'):
#         '''判断是否是字母'''
#         char += 1
#     else:
#         '''判断是否是下划线'''
#         xhx += 1
#
# print(num, char, xhx)

# 第二种方式：
# a = '1234abcABCDE_'
# num = 0  # 记录数字的个数
# char = 0  # 记录字符的个数
# xhx = 0  # 记录下划线的个数
# for i in a:
#     if i.isdigit():
#         '''判断是否是数字'''
#         num += 1
#     elif i.isalpha():
#         '''判断是否是字母'''
#         char += 1
#     else:
#         '''判断是否是下划线'''
#         xhx += 1
#
# print(num, char, xhx)