#编写map/reduce 函数测试 def normalize(name): return name[:1].upper()+name[1:].lower() # 测试: L1 = ['adam', 'LISA', 'barT'] L2 = list(map(normalize, L1)) print(L2)
#Python提供的sum()函数可以接受一个list并求和,请编写一个prod()函数,可以接受一个list并利用reduce()求积: from functools import reduce def prod(L): def add(x, y): return x * y return reduce(add , L) print('3 * 5 * 7 * 9 =', prod([3, 5, 7, 9])) if prod([3, 5, 7, 9]) == 945: print('测试成功!') else: print('测试失败!')
#利用map和reduce编写一个str2float函数,把字符串'123.456'转换成浮点数123.456 from functools import reduce DIGITS = {'0':0,'1':1,'2':2,'3':3,'4':4,'5':5,'6':6,'7':7,'8':8,'9':9} def str2float(s): def ch(ch): return DIGITS[ch] index = s.find('.') #return reduce(lambda x, y:x * 10 + y, map(ch,s[:index]))+0.1*reduce(lambda x, y: x / 10 + y, map(ch, s[index+1:][::-1])) return reduce(lambda x, y:x * 10 + y, map(ch,s[:index]))+0.1*reduce(lambda x, y: x / 10 + y, map(ch, s[len(s) - 1 : index:-1])) print('str2float(\'123.456\') =', str2float('123.456')) if abs(str2float('123.456') - 123.456) < 0.00001: print('测试成功!') else: print('测试失败!')
兄弟,第一题如果名字前面有空格就不行啦
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