我正在尝试创建一个可以绘制用户编写的函数的程序。该图来自参数函数。 我在python中使用matplotlib，但我可以这样做，用户将convert转换为matplotlib使用的函数。 你能帮我吗？或者你能告诉我其他python的图书馆吗？ 这是我的代码和我尝试过的内容：
import matplotlib as mpl
from mpl_toolkits.mplot3d import Axes3D
import matplotlib.pyplot as plt
from matplotlib.widgets import CheckButtons
from numpy import *
go=False
inputX=raw_input("Write the function for X: ")
inputY=raw_input("Write the function for Y: ")
inputZ=raw_input("Write the function for Z: ")
if len(inputX)>0 and len(inputY)>0 and len(inputZ)>0:
go=True
if go==True:
mpl.rcParams['legend.fontsize'] = 10
fig = plt.figure()
ax = fig.gca(projection='3d')
t = linspace(-4 * pi, 4 * pi, 200)
#I would like that the user input convert in the function for each "axis"
z = t
x = sin(t)
y = cos(t)
ax.plot(x, y, z, label='Test')
ax.legend()
plt.show()
在第一个中，我只检查了每个输入的len，但是当我尝试将输入传递给函数时，matplotlib给了我一个错误，并且因为用户输入是一个字符串没有所需的变量类型
感谢您的帮助，对不起我的英语。
答案 0 :(得分：0)
我修改了this pyparsing program，接受t作为变量：
from pyparsing import Literal,CaselessLiteral,Word,Combine,Group,Optional,\
ZeroOrMore,Forward,nums,alphas
from numpy import *
import operator
exprStack = []
def pushFirst( strg, loc, toks ):
exprStack.append( toks[0] )
def pushUMinus( strg, loc, toks ):
if toks and toks[0]=='-':
exprStack.append( 'unary -' )
#~ exprStack.append( '-1' )
#~ exprStack.append( '*' )
bnf = None
def BNF():
"""
expop :: '^'
multop :: '*' | '/'
addop :: '+' | '-'
integer :: ['+' | '-'] '0'..'9'+
atom :: PI | E | real | T | fn '(' expr ')' | '(' expr ')'
factor :: atom [ expop factor ]*
term :: factor [ multop factor ]*
expr :: term [ addop term ]*
"""
global bnf
if not bnf:
point = Literal( "." )
e = CaselessLiteral( "E" )
fnumber = Combine( Word( "+-"+nums, nums ) +
Optional( point + Optional( Word( nums ) ) ) +
Optional( e + Word( "+-"+nums, nums ) ) )
ident = Word(alphas, alphas+nums+"_$")
plus = Literal( "+" )
minus = Literal( "-" )
mult = Literal( "*" )
div = Literal( "/" )
lpar = Literal( "(" ).suppress()
rpar = Literal( ")" ).suppress()
addop = plus | minus
multop = mult | div
expop = Literal( "^" )
pi = CaselessLiteral( "PI" )
t = CaselessLiteral( "T" )
expr = Forward()
atom = (Optional("-") + ( pi | e | t | fnumber | ident + lpar + expr + rpar ).setParseAction( pushFirst ) | ( lpar + expr.suppress() + rpar )).setParseAction(pushUMinus)
# by defining exponentiation as "atom [ ^ factor ]..." instead of "atom [ ^ atom ]...", we get right-to-left exponents, instead of left-to-righ
# that is, 2^3^2 = 2^(3^2), not (2^3)^2.
factor = Forward()
factor << atom + ZeroOrMore( ( expop + factor ).setParseAction( pushFirst ) )
term = factor + ZeroOrMore( ( multop + factor ).setParseAction( pushFirst ) )
expr << term + ZeroOrMore( ( addop + term ).setParseAction( pushFirst ) )
bnf = expr
return bnf
# map operator symbols to corresponding arithmetic operations
epsilon = 1e-12
opn = { "+" : operator.add,
"-" : operator.sub,
"*" : operator.mul,
"/" : operator.truediv,
"^" : operator.pow }
fn = { "sin" : sin,
"cos" : cos,
"tan" : tan,
"abs" : abs,
"trunc" : lambda a: int(a),
"round" : round,
"sgn" : lambda a: abs(a)>epsilon and cmp(a,0) or 0}
def evaluateStack( s ):
op = s.pop()
if op == 'unary -':
return -evaluateStack( s )
if op in "+-*/^":
op2 = evaluateStack( s )
op1 = evaluateStack( s )
return opn[op]( op1, op2 )
elif op == "PI":
return math.pi # 3.1415926535
elif op == "E":
return math.e # 2.718281828
elif op == "T":
return linspace(-4 * pi, 4 * pi, 200)
elif op in fn:
return fn[op]( evaluateStack( s ) )
elif op[0].isalpha():
return 0
else:
return float( op )
def compute(s):
global exprStack
exprStack = []
results = BNF().parseString( s )
val = evaluateStack( exprStack[:] )
return val
fun=raw_input("Please input a function to be evaluated: ")
print compute(fun)
例如，该程序执行以下操作：
Please input a function to be evaluated: 2+sin(t)
[ 2. 2.12595971 2.24991296 2.36988529 2.4839656 2.59033669
2.68730414 2.77332333 2.84702403 2.90723225 2.95298891 2.98356514
2.99847388 2.99747765 2.98059231 2.94808684 2.90047903 2.83852724
2.7632183 2.67575185 2.57752115 2.47009096 2.35517255 2.2345965
2.1102835 1.98421376 1.85839548 1.73483286 1.61549416 1.50228037
1.39699489 1.30131485 1.21676437 1.14469026 1.08624063 1.04234653
1.01370716 1.00077873 1.00376718 1.0226249 1.05705151 1.1064986
1.17017854 1.24707694 1.33596886 1.43543832 1.54390084 1.6596287
1.78077842 1.90542019 2.03156855 2.15721404 2.28035523 2.39903056
2.51134962 2.61552324 2.70989202 2.79295273 2.86338228 2.92005876
2.96207936 2.98877473 2.99971963 2.99473972 2.97391431 2.93757514
2.88630108 2.82090888 2.74244018 2.65214495 2.55146151 2.44199369
2.32548523 2.20379202 2.07885255 1.95265701 1.82721561 1.70452655
1.58654417 1.47514784 1.37211203 1.27907802 1.19752779 1.12876036
1.07387115 1.03373451 1.00898979 1.00003115 1.0070013 1.0297892
1.06803187 1.12112012 1.1882083 1.26822773 1.35990378 1.46177609
1.57222193 1.68948197 1.81168833 1.93689437 2.06310563 2.18831167
2.31051803 2.42777807 2.53822391 2.64009622 2.73177227 2.8117917
2.87887988 2.93196813 2.9702108 2.9929987 2.99996885 2.99101021
2.96626549 2.92612885 2.87123964 2.80247221 2.72092198 2.62788797
2.52485216 2.41345583 2.29547345 2.17278439 2.04734299 1.92114745
1.79620798 1.67451477 1.55800631 1.44853849 1.34785505 1.25755982
1.17909112 1.11369892 1.06242486 1.02608569 1.00526028 1.00028037
1.01122527 1.03792064 1.07994124 1.13661772 1.20704727 1.29010798
1.38447676 1.48865038 1.60096944 1.71964477 1.84278596 1.96843145
2.09457981 2.21922158 2.3403713 2.45609916 2.56456168 2.66403114
2.75292306 2.82982146 2.8935014 2.94294849 2.9773751 2.99623282
2.99922127 2.98629284 2.95765347 2.91375937 2.85530974 2.78323563
2.69868515 2.60300511 2.49771963 2.38450584 2.26516714 2.14160452
2.01578624 1.8897165 1.7654035 1.64482745 1.52990904 1.42247885
1.32424815 1.2367817 1.16147276 1.09952097 1.05191316 1.01940769
1.00252235 1.00152612 1.01643486 1.04701109 1.09276775 1.15297597
1.22667667 1.31269586 1.40966331 1.5160344 1.63011471 1.75008704
1.87404029 2. ]
所以基本上compute函数将评估简单表达式，并在使用t时提供linspace（var）。如果需要，您可以扩展它。我认为你可以从这里整合你需要的东西，使你的程序工作。 ：）