Python 如果代码不返回任何值，而应返回指定值

多次检查我的循环。我发现不了一个错误，需要另一双眼睛来帮助。下面的代码返回none，但它应该返回一个特定的值

我已经检查了self.mdlname的值，它是正确的。我认为这与第一个函数curr有关。未正确地将值重新指定给self.currency。我看不出它应该返回none值的其他原因

spartSABR函数后的以下ommitted函数

import string

datatype = "Inflation SABR Vol ATM ZC"
dataconvention = "UK-RPI-ZERO-COUPON-SWAP-RATE"
mdlname = 'INFLATION_SABR'
t1 = 'should-send-back-none'


class srtqualifier:
    def __init__(self,mdlname,datatype, dataconvention,t1):
        self.mdlname = mdlname
        self.datatype = datatype
        self.dataconvention = dataconvention
        self.t1 = t1 ##TO BE REMOVED, ONLY USE FOR TESTING##
        self.tempholder =  self.dataconvention.split("-")
        self.currency = self.tempholder[0]

    def curr(self):
        if self.mdlname == 'INFLATION_SABR':
            inflationcurrency = {'UK':'GBP','FR':'EUR','EU':'EUR','US':'USD'}
            self.currency = inflationcurrency.get(self.currency)
            return self.currency

    def spartSABR(self):
        if self.dataconvention == 'JPY-SWAPTION-CLEAREDPHYSICAL-SEMI-ACT365F':
            return 'LIBOR_JPY_6M'
        elif self.dataconvention == 'USD-SIFMA Municipal Swap Index-1W-SWAPTION-PHYSICAL-SEMI-BOND':
            secondpartsp = self.tempholder[1].split(" ")
            secondpartsp.append(self.tempholder[2])
            separator = "_"
            secondpart = separator.join(secondpartsp[1:len(secondpartsp)])
            secondpart = secondpart.upper()
            return secondpart
        elif self.mdlname == 'INFLATION_SABR':
            secondpartsp = self.tempholder[0:2]
            secondpartsp = secondpartsp.append([self.currency,'1Y'])
            return secondpartsp
        else:
            secondpartsp = self.tempholder[1].split(" ")
            secondpartsp.append(self.tempholder[2])
            secondpartsp.insert(1,self.currency)
            separator = "_"
            secondpart = separator.join(secondpartsp)
            secondpart = secondpart.upper()
            return secondpart

test1 = srtqualifier(mdlname,datatype,dataconvention,t1)
print (test1.curr())
print (test1.spartSABR())

---

secondpartsp=secondpartsp.append（[self.currency，'1Y']） 这会将[self.currency，'1Y']追加到secondpartsp。但是append方法不会返回任何内容（它不会返回任何内容），它不会像您所想的那样返回列表。因此，接下来发生的事情是将结果（无）分配给secondpartsp，现在secondpartsp为空。

import string

datatype = "Inflation SABR Vol ATM ZC"
dataconvention = "UK-RPI-ZERO-COUPON-SWAP-RATE"
mdlname = 'INFLATION_SABR'
t1 = 'should-send-back-none'


class srtqualifier:
    def __init__(self,mdlname,datatype, dataconvention,t1):
        self.mdlname = mdlname
        self.datatype = datatype
        self.dataconvention = dataconvention
        self.t1 = t1 ##TO BE REMOVED, ONLY USE FOR TESTING##
        self.tempholder =  self.dataconvention.split("-")
        self.currency = self.tempholder[0]

    def curr(self):
        if self.mdlname == 'INFLATION_SABR':
            inflationcurrency = {'UK':'GBP','FR':'EUR','EU':'EUR','US':'USD'}
            self.currency = inflationcurrency.get(self.currency)
            return self.currency

    def spartSABR(self):
        if self.dataconvention == 'JPY-SWAPTION-CLEAREDPHYSICAL-SEMI-ACT365F':
            return 'LIBOR_JPY_6M'
        elif self.dataconvention == 'USD-SIFMA Municipal Swap Index-1W-SWAPTION-PHYSICAL-SEMI-BOND':
            secondpartsp = self.tempholder[1].split(" ")
            secondpartsp.append(self.tempholder[2])
            separator = "_"
            secondpart = separator.join(secondpartsp[1:len(secondpartsp)])
            secondpart = secondpart.upper()
            return secondpart
        elif self.mdlname == 'INFLATION_SABR':
            secondpartsp = self.tempholder[0:2]
            secondpartsp.append([self.currency,'1Y'])
            return secondpartsp
        else:
            secondpartsp = self.tempholder[1].split(" ")
            secondpartsp.append(self.tempholder[2])
            secondpartsp.insert(1,self.currency)
            separator = "_"
            secondpart = separator.join(secondpartsp)
            secondpart = secondpart.upper()
            return secondpart

test1 = srtqualifier(mdlname,datatype,dataconvention,t1)
print (test1.curr())
print (test1.spartSABR())

---

基于恒河湿婆克里希纳提供的逻辑。我解决了这个问题。我不需要同时赋值和追加。解决方案如下：

def spartSABR(self):
        if self.dataconvention == 'JPY-SWAPTION-CLEAREDPHYSICAL-SEMI-ACT365F':
            return 'LIBOR_JPY_6M'
        elif self.dataconvention == 'USD-SIFMA Municipal Swap Index-1W-SWAPTION-PHYSICAL-SEMI-BOND':
            secondpartsp = self.tempholder[1].split(" ")
            secondpartsp.append(self.tempholder[2])
            separator = "_"
            secondpart = separator.join(secondpartsp[1:len(secondpartsp)])
            secondpart = secondpart.upper()
            return secondpart
        elif self.mdlname == 'INFLATION_SABR':
            secondpartsp = self.tempholder[0:2]
            print(self.tempholder[0:2])
            secondpartsp.append(self.currency)## I was doing secondpartsp= secondpartsp.append(self.currency)
            secondpartsp.append('1Y')
            separator = "_"
            secondpartsp = separator.join(secondpartsp)
            return secondpartsp
        else:
            secondpartsp = self.tempholder[1].split(" ")
            secondpartsp.append(self.tempholder[2])
            secondpartsp.insert(1,self.currency)
            separator = "_"
            secondpart = separator.join(secondpartsp)
            secondpart = secondpart.upper()
            return secondpart

---

curr

中的

return

在

if

语句中。这就是你想要的吗？这是错误的：

secondpartsp=secondpartsp.append（[self.currency，'1Y']）

append

返回

None

，在返回前覆盖

secondpartsp

。它可能重复。@MisterMiyagi在返回前需要覆盖它returned@MatthewStrawbridge是的，这就是我们的意图