【每日一题0706】 反转数字

给定一个整数 x ,返回 x 反转后的结果

def fn(x):
  pass
assert fn(31) == 13
assert fn(-123) == -321
assert fn(10) == 1

题目来源 :反转数字_牛客题霸_牛客网

s =’’
x = input(“请输入一个整数:”)
if x[0] == ‘-’:
a = x[1:] + x[0]
else:
a = x
for i in a:
s = i + s
print(int(s))

def fn(x: int):
    _final = int(f"-{''.join(list(reversed([i for i in str(x)[1:]])))}") if str(x)[0] == "-" else int(
        ''.join(list(reversed([i for i in str(x)]))))
    return _final if -(2 ** 31) <= _final <= 2 ** 31 - 1 else 0

编写代码的时候加上三个 `号 然后写上python 会给展示python格式
类似这样
image

def fn(x):
if str(x)[0]=="-":
c=[j for j in str(x)[1:]]
c.reverse()
return -int(’’.join([str(i) for i in c]))
else:
c = [j for j in str(x)]
c.reverse()
return int(’’.join([str(i) for i in c]))

断言没有报错,但总感觉写的有点糙

def fn(x):
    x=str(x)
    if x[0] =='-':
        res='-'
        for i in range(len(x)):
            if i>0:
                res=res+x[-i]
    else:
        res=''
        for i in range(len(x)):
            res=res+x[-i-1]
    return int(res)
print(fn(31),fn(-123),fn(10))
assert fn(31)==13
assert fn(-123)==-321
assert fn(10)==1
def fn(x):
    '''
    反转整数
    :param x: 
    :return: 
    '''
    b=[]
    res=0
    c=''
    if -9<=x<=9:
        return x
    else:
        if x<=-10:
            res='-'
            x=abs(x)
        while x>9:
            a=x%10
            b.append(a)
            x=x//10
        b.append(x)
        for i in b:
            c=c+str(i)
        if res=='-':
            res=res+c
            return int(res)
        else:
            return int(c)

assert fn(312) == 213
assert fn(-123) == -321
assert fn(10) == 1
def fn(x):
  reverse_num = int(str(abs(x))[::-1])
  return 0-reverse_num if x < 0 else reverse_num

assert fn(31) == 13
assert fn(-123) == -321
assert fn(10) == 1

题解:

def fn(x):
    return int(str(x)[::-1]) if x > 0 else 0 - int(str(x)[1:][::-1])

assert fn(31) == 13
assert fn(-123) == -321
assert fn(10) == 1

:partying_face: :partying_face: :partying_face: :partying_face: :partying_face: :partying_face:

def fun_reverse(x):
if x > 0:
return int(str(x)[::-1])
else:
return int(str(x)[1:][::-1])

···
‘’.join(sorted(list(str(x)),reverse=True))
···

def fn(x):
    L = list(str(x))
    L.reverse()
    return int(''.join(L)) if x>0 else int('-' + ''.join(L[:-1]))

assert fn(31) == 13
assert fn(-123) == -321
assert fn(10) == 1
def fn(x):
    return int(str(x)[::-1]) if '-' not in str(x) else int('-' + str(x)[1:][::-1])


assert fn(31) == 13
assert fn(-123) == -321
assert fn(10) == 1
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