python中用户matplotlib的输入函数

我正在尝试制作一个程序，可以绘制用户编写的函数。该图来自一个参数函数。 我在python中使用matplotlib，但我可以做到用户将转换写入matplotlib使用的函数。 你能帮我吗？或者你能给我推荐其他python库吗？ 以下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()

在第一个例子中，我只是检查了每个输入的len，但是当我试图将输入传递给函数matplotlib时，给了我一个错误，因为用户输入是一个字符串，而不是所需的变量类型

谢谢你的帮助，对我的英语很抱歉

I修改为接受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)

---

因此，基本上，compute函数将计算简单表达式，如果使用t，则提供一个linspace变量。如果你愿意，你可以扩展它。我认为你可以从这里整合你需要的东西，使你的计划发挥作用

你能解释一下为什么x，y，z有if条件，而它们后来被定义了吗？你的意思是：如果列宁普特x>0，列宁普特y>0，列宁普特z>0？这是因为我只想控制何时显示图形。我认为，首先要问方程，然后给出用户在matplotlib中写的方程，然后显示图表。谢谢你的评论。

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.        ]