week7

视频总结

final exam ：
报错：
'int' object is not callable，此参数已被声明为int，不可作为函数调用
stackoverflow:https://stackoverflow.com/questions/9767391/typeerror-int-object-is-not-callable
原因：调用函数时传参了int类型，实际上应该参数定义是函数，之后的函数调用就会报此错误

python中的self

• __init__函数默认的第一个参数
• 类中方法的第一参数永远是类的本身实例变量self，并且调用时，不用传递

第二题答案

# Paste your entire definition of the edx class in this box
class edx(object):
    # edc类
    def __init__(self, courses):
        # 初始化 我的课程
        # 用一个数组初始化
        self.myCourses = []
        for course in courses:
            self.myCourses.append(courseInfo(course))

    def setGrade(self, grade, course="6.01x"):
        """
        grade: integer greater than or equal to 0 and less than or equal to 100
        course: string 

        This method sets the grade in the courseInfo object named by `course`.   

        If `course` was not part of the initialization, then no grade is set, and no
        error is thrown.

        The method does not return a value.
        """
        #   fill in code to set the grade
        for index in range(len(self.myCourses)):
            if(self.myCourses[index].courseName == course):
                self.myCourses[index].setGrade(grade)

    def getGrade(self, course="6.02x"):
        """
        course: string 

        This method gets the grade in the the courseInfo object named by `course`.

        returns: the integer grade for `course`.  
        If `course` was not part of the initialization, returns -1.
        """
        #   fill in code to get the grade
        for index in range(len(self.myCourses)):
            if(self.myCourses[index].courseName == course):
               return self.myCourses[index].getGrade()

    def setPset(self, pset, score, course="6.00x"):
        """
        pset: a string or a number
        score: an integer between 0 and 100
        course: string

        The `score` of the specified `pset` is set for the
        given `course` using the courseInfo object.

        If `course` is not part of the initialization, then no pset score is set,
        and no error is thrown.
        """
        #   fill in code to set the pset
        for index in range(len(self.myCourses)):
            if(self.myCourses[index].courseName == course):
                self.myCourses[index].setPset(pset,score)
               


    def getPset(self, pset, course="6.00x"):
        """
        pset: a string or a number
        course: string        

        returns: The score of the specified `pset` of the given
        `course` using the courseInfo object.
        If `course` was not part of the initialization, returns -1.
        """
        #   fill in code to get the pset
        for index in range(len(self.myCourses)):
            if(self.myCourses[index].courseName == course):
                self.myCourses[index].getPset(pset)

chp 11

PyLab类似matlab绘图，练习绘图，完整代码如下：

import pylab
class Mortgage(object):
    """建立不同种类抵押贷款的抽象类"""
def __init__(self, loan, annRate, months):
    self.loan = loan
    self.rate = annRate/12.0
    self.months = months
    self.paid = [0.0]
    self.outstanding = [loan]
    self.payment = findPayment(loan, self.rate, months)
    self.legend = None #description of mortgage
def makePayment(self):
    self.paid.append(self.payment)
    reduction = self.payment - self.outstanding[-1]*self.rate
    self.outstanding.append(self.outstanding[-1] - reduction)
def getTotalPaid(self):
    return sum(self.paid)
def __str__(self):
    return self.legend
def plotPayments(self, style):
    pylab.plot(self.paid[1:], style, label = self.legend)
def plotBalance(self, style):
    pylab.plot(self.outstanding, style, label = self.legend)
def plotTotPd(self, style):
    totPd = [self.paid[0]]
    for i in range(1, len(self.paid)):
        totPd.append(totPd[-1] + self.paid[i])
    pylab.plot(totPd, style, label = self.legend)

def plotNet(self, style):
    totPd = [self.paid[0]]
    for i in range(1, len(self.paid)):
        totPd.append(totPd[-1] + self.paid[i])
    equityAcquired = pylab.array([self.loan] * len(self.outstanding))
    equityAcquired = equityAcquired - pylab.array(self.outstanding)
    net = pylab.array(totPd) – equityAcquired
    pylab.plot(net, style, label = self.legend)