python 练习-2

#将字符串元素反序输出
def reverseWords(str):
return ’ ‘.join(reversed(str.split(’ ')))
print(reverseWords(“hello world!”))

#给定数字生成列表
#例1
def monkey_count(n):
return [i+1 for i in range(n)]
print(monkey_count(5))

#给出操作符，返回数学运算结果
def basic_op(operator, value1, value2):
if operator == ‘+’:
return value1 + value2
if operator == ‘-’:
return value1 - value2
if operator == '’:
return value1 * value2
if operator == ‘/’:
return value1 / value2
print(basic_op("+",1,1))
print(basic_op("-",1,1))
print(basic_op("",1,1))
print(basic_op("/",1,1))

#将十六进制转为十进制
def hex_to_dec(s):
return int(s,16)
print(hex_to_dec(“a”))
print(hex_to_dec(“b”))

#计算世纪
def century(year):
return (year + 99) // 100
print(century(2019))

#楼梯
def draw_stairs(n):
return ‘\n’.join(’ '*i+‘I’ for i in range(n))
print(draw_stairs(3))

#求平均数
def find_average(array):
return sum(array) / len(array) if array else 0
print(find_average([1,2,3,4]))

#格式化输出数字，长度为5，用0补齐
def solution(value):
return “Value is %05d”%value
print(solution(10)
print(solution(5))