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发表于 2010-4-20 09:12:11
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来自 北京
本帖最后由 ggggwhw 于 2010-4-20 13:56 编辑
为了避免垒砖之嫌,我删去了下面的哪些没有用的帖子只剩下了最后的结果.为了不产生意外的结果,需要注意:
(1)不能省略乘号,至少应该将乘号写成*或者×或者"空格"的形式;
(2)所有的自定义函数需要首字母大写.
下面是我写的代码:- In[427]:= Biaozhun // Remove
- Biaozhun[str1_] :=
- Module[{char1, len1, yunsuanfu, zimubiao, pos2, len2, cnt, j, k},
- char1 = Characters[str1];
- len1 = Length[char1];
- yunsuanfu = {"+", "-", "*", "/", "^", "(", ")", "[", "]", "{", "}",
- " ", "\[Times]", "\n"};
- zimubiao =
- Flatten[Table[{FromCharacterCode[i + 64],
- FromCharacterCode[i + 96]}, {i, 1, 26}]];
- For[j = 2, j <= len1, j++,
- If[char1[[j]] == "(" && ! MemberQ[yunsuanfu, char1[[j - 1]]],
- char1[[j]] = "["];];
- pos2 = Flatten[Position[char1, "["]
- ];
- len2 = Length@pos2;
- For[j = 1, j <= len2, j++,
- For[k = pos2[[j]] + 1; cnt = 0, k <= len1, k++,
- If[char1[[k]] == "(", cnt += 1];
- If[char1[[k]] == ")",
- If[cnt == 0, char1[[k]] = "]"; Break[], cnt -= 1];];];
- For[k = pos2[[j]] - 1, k >= 1, k--,
- If[! MemberQ[zimubiao, char1[[k]]],
- char1[[k + 1]] = ToUpperCase[char1[[k + 1]]]; Break[];];
- If[k == 1, char1[[k]] = ToUpperCase[char1[[k]]]; Break[];];
- ];
- ];
- ToExpression[StringJoin[char1]]
- ];
- str = "(r*sin(A)-rho*sin(3*B))*(cos(beta)-sin(beta)*cos(3*B)-sin(beta)
- *sin(3*B)*tan(B))-(r*cos(A)-rho*cos(beta)*cos(3*B))*tan(B)";
- Biaozhun[str]
- Out[430]= -(r Cos[A] - rho Cos[3 B] Cos[beta]) Tan[
- B] + (r Sin[A] - rho Sin[3 B]) (Cos[beta] - Cos[3 B] Sin[beta] -
- Sin[3 B] Sin[beta] Tan[B])
复制代码 下面是Mathematica 自带的函数:- In[290]:= str1 = \
- "(r*sin(A)-rho*sin(3*B))*(cos(beta)-sin(beta)*cos(3*B)-sin(beta)*sin(\
- 3*B)*tan(B))-(r*cos(A)-rho*cos(beta)*cos(3*B))*tan(B)"; \
- ToExpression[str1, TraditionalForm]
- Out[290]= -(r Cos[A] - rho Cos[3 B] Cos[beta]) Tan[
- B] + (r Sin[A] - rho Sin[3 B]) (Cos[beta] - Cos[3 B] Sin[beta] -
- Sin[3 B] Sin[beta] Tan[B])
复制代码 |
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