给定一个方程式：f(x) = axn ，其中只包含一个未知项，并且a 和 n 都是整数。例如：f(x) = 3x2，f(x) = 5。
我们的任务是编写一个函数，把这个f(x)方程式的内容作为参数，格式为字符串。返回求导后的结果，字符串格式。
数学中的求导公式是：f(x)=axn，则f‘(x) = naxn-1。若n=0，则结果始终为0.
示例：
输入： “3x^2”，输出：“6x”。
输入： “6x^-2” ，输出： “-12x^-3”。
输入： “5x”，输出：“5”。
输入： “42”，输出：“0”。
题目难度：简单
题目来源：CodeWars：Derivatives of type x^n
def solution(fx: str) -> str
# your code here
assert solution("3x^2") == "6x"
assert solution("6x^-2") == "-12x^-3"
assert solution("5x") == "5"
assert solution("42") == "0"
def solution(fx: str) -> str:
if '^' in fx:
f = fx.split('x^')
if f[1] == "2":
return str(int(f[0]) * int(f[1])) + 'x'
else:
return str(int(f[0]) * int(f[1])) + 'x^' + str(int(f[1]) - 1)
elif 'x' in fx:
f = fx.split('x')
return f[0]
else:
return '0'
assert solution("3x^2") == "6x"
assert solution("6x^-2") == "-12x^-3"
assert solution("5x") == "5"
assert solution("42") == "0"
if "^" in fx:
list1 = fx.split("x^")
n = int(list1[0]) * int(list1[1])
m = int(list1[1]) - 1
if m == 1:return "".join(str(n) + "x")
else:return "".join(str(n) + "x^" + str(m))
elif "x" in fx:return fx[:-1]
else:return "0"
def solution(fx: str) -> str:
n = 1 if ('x' in fx and '^' not in fx) else 0 if 'x^' not in fx else None
f_list = fx.split('x') if n == 1 else fx.split('x^')
if n is None:
n = int(f_list[-1])
return str(int(f_list[0]) * n) + ('x' if n not in [0, 1] else '') + ('' if n in [1, 2, 0, None] else '^' + str(n - 1))
assert solution("3x^2") == "6x"
assert solution("6x^-2") == "-12x^-3"
assert solution("5x") == "5"
assert solution("42") == "0"
def solution4(fx: str) → str:
if “x” not in fx:
return “0”
else:
if “^” not in fx:
num = fx.split(“x”)
return num[0]
else:
num = fx.split(“x^”)
a = int(num[0])
b = int(num[1])
if b == 2:
return str(ab) + “x”
else:
return str(ab) + “x^” + str(b-1)
assert solution4(“3x^2”) == “6x”
assert solution4(“6x^-2”) == “-12x^-3”
assert solution4(“5x”) == “5”
assert solution4(“42”) == “0”
def solution(fx: str) -> str:
params = fx.split('x^')
if len(params) == 1:
if 'x' in fx:
return fx.replace('x', '')
else:
return '0'
elif params[1] == '2':
return str(eval(f"{params[0]} * {params[1]}")) + 'x'
else:
return str(eval(f"{params[0]} * {params[1]}")) + 'x^' + str(eval(f"{params[1]}- 1"))
assert solution("3x^2") == "6x"
assert solution("6x^-2") == "-12x^-3"
assert solution("5x") == "5"
assert solution("42") == "0"
def solution(f: str) -> str:
if "^" not in f:
if "x" not in f:
return "0"
return f[0]
if "^" in f:
a, b = f.split("^")
if b == '2':
return str(int(a[:-1]) * int(b)) + "x"
return str(int(a[:-1]) * int(b)) + "x^" + str(int(b) - 1)
def solution(fx: str) -> str:
x_posi = fx.find('x')
if 'x' in fx:
if '^' in fx:
coeff = int(fx[:x_posi])
exp = int(fx[x_posi + 2:])
coeff *= exp
exp -= 1
deri = str(coeff)
if exp:
deri += 'x'
if exp != 1: deri += '^' + str(exp)
return deri
else:
return fx[:-1]
pass
else:
return '0'
# your code here
assert solution("3x^2") == "6x"
assert solution("6x^-2") == "-12x^-3"
assert solution("5x") == "5"
assert solution("42") == "0"
def solution(fx: str) -> str:
if "x" in fx:
lis = fx.split("x")
if "^" not in fx:
return lis[0]
else:
a = int(lis[0])
b = int(lis[1][1:])
if b == 2:
return f"{a * b}x"
return f"{a * b}x^{b - 1}"
else:
return "0"
def solution(fx: str) -> str:
an = fx.split('x')
if len(an)==1:
return '0'
elif an[1]=='':
return an[0]
else:
a = int(an[0])
xn = an[1].split('^')
n = int(xn[1])
return str(a*n)+'x' if n-1 == 1 else str(a*n)+'x^'+str(n-1)
def solution(fx: str) -> str:
if '^' in fx:
fx_list = fx.split('x')
if fx_list[1] == '^2':
return str(int(fx_list[0]) * int(fx_list[1][fx_list[1].index('^') + 1:])) + 'x'
else:
return str(int(fx_list[0]) * int(fx_list[1][fx_list[1].index('^') + 1:])) + 'x' + '^' + str(
int(fx_list[1][1:]) - 1)
else:
if 'x' in fx:
return fx[:fx.index('x')]
else:
return '0'
assert solution("3x^2") == "6x"
assert solution("6x^-2") == "-12x^-3"
assert solution("5x") == "5"
assert solution("42") == "0"