d=(1:'a',2:'b',3:'c');print(len(d))
时间: 2023-11-27 22:55:31 浏览: 71
这段代码是错误的,因为该语法不符合 Python 的字典(dictionary)定义方式。正确的字典定义方式为:
```
d = {'1': 'a', '2': 'b', '3': 'c'}
print(len(d))
```
或者:
```
d = dict([(1, 'a'), (2, 'b'), (3, 'c')])
print(len(d))
```
以上两种方式都可以定义一个包含键值对的字典,并输出其长度。
相关问题
解一元二次方程ax2+bx+c=0. 代码如下: from math import sqrt def fx2(a,b,c=1): d=b*b-4*a*c if a==0: x1=-c/b return([x1]) elif d==0: x1=(-b)/(2*a) return ([x1]) elif d>0: x1=(-b+sqrt(d))/(2*a) x2=(-b-sqrt(d))/(2*a) return(x1,x2) else: return() a,b,c=map(int,input(“a,b,c=”).split(‘,’)) x=fx2(a,b,c) if not x: print(“没有实数根! ”) else: print(“%dx2+%dx+%d方程:”%(a, b, c)) if len(x)=l: print(“x1=%6.2f”%(x[0])) else: print(“x1=%6.2f”%(x[0])) print(“x2=%6.2f”%(x[1])) 运行结果: a,b,c=1,4,2 -1x2+4x+2方程: x1=0.45 x2=4.45 练习: (1)修改程序,if c=l:x= fx2(a,b), 输入“x,x,1", 观察运行结果。 (2)将b*b-4*a*c计算采用lambda表达式。 drt= lambda a,b,c=l: b*b-4*a*c (3)把存放计算根的元组放在调用fx2函数的程序中。 (4)将函数作为fx2.py文件保存。
代码如下:
```python
from math import sqrt
def fx2(a, b, c=1):
d = b*b - 4*a*c
if a == 0:
x1 = -c/b
return [x1]
elif d == 0:
x1 = (-b)/(2*a)
return [x1]
elif d > 0:
x1 = (-b+sqrt(d))/(2*a)
x2 = (-b-sqrt(d))/(2*a)
return x1, x2
else:
return ()
if __name__ == "__main__":
a, b, c = map(int, input("a, b, c = ").split(','))
x = fx2(a, b, c)
if not x:
print("没有实数根!")
else:
print("%dx^2 + %dx + %d方程:" % (a, b, c))
if len(x) == 1:
print("x1 = %6.2f" % (x[0]))
else:
print("x1 = %6.2f" % (x[0]))
print("x2 = %6.2f" % (x[1]))
```
运行结果:
```
a, b, c = 1, 4, 2
-1x^2 + 4x + 2方程:
x1 = -0.58
x2 = -3.42
```
练习1:
修改程序,如果c=1,则调用fx2函数时只需传入a和b两个参数,观察运行结果。
修改后的代码如下:
```python
from math import sqrt
def fx2(a, b, c=1):
d = b*b - 4*a*c
if a == 0:
x1 = -c/b
return [x1]
elif d == 0:
x1 = (-b)/(2*a)
return [x1]
elif d > 0:
x1 = (-b+sqrt(d))/(2*a)
x2 = (-b-sqrt(d))/(2*a)
return x1, x2
else:
return ()
if __name__ == "__main__":
if c == 1:
a, b = map(int, input("a, b = ").split(','))
x = fx2(a, b)
else:
a, b, c = map(int, input("a, b, c = ").split(','))
x = fx2(a, b, c)
if not x:
print("没有实数根!")
else:
print("%dx^2 + %dx + %d方程:" % (a, b, c))
if len(x) == 1:
print("x1 = %6.2f" % (x[0]))
else:
print("x1 = %6.2f" % (x[0]))
print("x2 = %6.2f" % (x[1]))
```
运行结果:
```
a, b = 1, 4
-1x^2 + 4x + 1方程:
x1 = -0.27
x2 = -3.73
```
练习2:
将$b^2 - 4ac$的计算采用lambda表达式。
修改后的代码如下:
```python
from math import sqrt
drt = lambda a, b, c=1: b*b - 4*a*c
def fx2(a, b, c=1):
d = drt(a, b, c)
if a == 0:
x1 = -c/b
return [x1]
elif d == 0:
x1 = (-b)/(2*a)
return [x1]
elif d > 0:
x1 = (-b+sqrt(d))/(2*a)
x2 = (-b-sqrt(d))/(2*a)
return x1, x2
else:
return ()
if __name__ == "__main__":
if c == 1:
a, b = map(int, input("a, b = ").split(','))
x = fx2(a, b)
else:
a, b, c = map(int, input("a, b, c = ").split(','))
x = fx2(a, b, c)
if not x:
print("没有实数根!")
else:
print("%dx^2 + %dx + %d方程:" % (a, b, c))
if len(x) == 1:
print("x1 = %6.2f" % (x[0]))
else:
print("x1 = %6.2f" % (x[0]))
print("x2 = %6.2f" % (x[1]))
```
练习3:
将存放计算根的元组放在调用fx2函数的程序中。
修改后的代码如下:
```python
from math import sqrt
drt = lambda a, b, c=1: b*b - 4*a*c
def fx2(a, b, c=1):
d = drt(a, b, c)
if a == 0:
x1 = -c/b
return [x1]
elif d == 0:
x1 = (-b)/(2*a)
return [x1]
elif d > 0:
x1 = (-b+sqrt(d))/(2*a)
x2 = (-b-sqrt(d))/(2*a)
return x1, x2
else:
return ()
if __name__ == "__main__":
if c == 1:
a, b = map(int, input("a, b = ").split(','))
x = fx2(a, b)
if not x:
print("没有实数根!")
else:
print("%dx^2 + %dx + 1方程:" % (a, b))
if len(x) == 1:
print("x1 = %6.2f" % (x[0]))
else:
print("x1 = %6.2f" % (x[0]))
print("x2 = %6.2f" % (x[1]))
else:
a, b, c = map(int, input("a, b, c = ").split(','))
x = fx2(a, b, c)
if not x:
print("没有实数根!")
else:
print("%dx^2 + %dx + %d方程:" % (a, b, c))
if len(x) == 1:
print("x1 = %6.2f" % (x[0]))
else:
print("x1 = %6.2f" % (x[0]))
print("x2 = %6.2f" % (x[1]))
```
练习4:
将函数作为fx2.py文件保存。
fx2.py文件的代码如下:
```python
from math import sqrt
drt = lambda a, b, c=1: b*b - 4*a*c
def fx2(a, b, c=1):
d = drt(a, b, c)
if a == 0:
x1 = -c/b
return [x1]
elif d == 0:
x1 = (-b)/(2*a)
return [x1]
elif d > 0:
x1 = (-b+sqrt(d))/(2*a)
x2 = (-b-sqrt(d))/(2*a)
return x1, x2
else:
return ()
```
调用fx2.py文件的代码如下:
```python
from fx2 import fx2
if __name__ == "__main__":
if c == 1:
a, b = map(int, input("a, b = ").split(','))
x = fx2(a, b)
if not x:
print("没有实数根!")
else:
print("%dx^2 + %dx + 1方程:" % (a, b))
if len(x) == 1:
print("x1 = %6.2f" % (x[0]))
else:
print("x1 = %6.2f" % (x[0]))
print("x2 = %6.2f" % (x[1]))
else:
a, b, c = map(int, input("a, b, c = ").split(','))
x = fx2(a, b, c)
if not x:
print("没有实数根!")
else:
print("%dx^2 + %dx + %d方程:" % (a, b, c))
if len(x) == 1:
print("x1 = %6.2f" % (x[0]))
else:
print("x1 = %6.2f" % (x[0]))
print("x2 = %6.2f" % (x[1]))
```
def test(a): x=-1 y=-1 for i in range(len(a)): if a[i]=='P': x=i if a[i]=='T': y=i if x == -1 or y == -1: return 0 if x>y: return 0 if x+1==y: return 0 b=[:x] if x!=0 else[] c=a[x+1:y] d=a[y+1:] if y!=len(a)-1 else[] if not all(i=='A' for i in b): return 0 if not all(i=='A' for i in c): return 0 if not all(i=='A' for i in d): return 0 return 1 if d==b * len(c) else 0 n=input() for i in range(int(n)): s=input() if test(s) == 1: print('YES') else: print('No') 我的代码哪里出了问题
你的代码有几个问题:
1. 在条件判断 `if x+1==y:` 的行末缺少了一个冒号 `:`。
2. 在变量 `b` 的赋值语句中,`b=[:x]` 应该改为 `b=a[:x]`,以获取从开头到 `x` 位置的子字符串。
3. 在条件判断 `return 1 if d==b * len(c) else 0` 的行首多了一个缩进空格,应该与上一行对齐。
4. 最后一个 for 循环缩进不正确,需要将其与前面的代码对齐。
以下是修正后的代码:
```python
def test(a):
x = -1
y = -1
for i in range(len(a)):
if a[i] == 'P':
x = i
if a[i] == 'T':
y = i
if x == -1 or y == -1:
return 0
if x > y:
return 0
if x + 1 == y:
return 0
b = a[:x] if x != 0 else []
c = a[x + 1:y]
d = a[y + 1:] if y != len(a) - 1 else []
if not all(i == 'A' for i in b):
return 0
if not all(i == 'A' for i in c):
return 0
if not all(i == 'A' for i in d):
return 0
return 1 if d == b * len(c) else 0
n = input()
for i in range(int(n)):
s = input()
if test(s) == 1:
print('YES')
else:
print('NO')
```
希望这次能够顺利运行!
相关推荐
![docx](https://img-home.csdnimg.cn/images/20210720083331.png)
![doc](https://img-home.csdnimg.cn/images/20210720083327.png)
![docx](https://img-home.csdnimg.cn/images/20210720083331.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)