python – 更高效的代码(看似太多if语句)

内容导读

互联网集市收集整理的这篇技术教程文章主要介绍了python – 更高效的代码(看似太多if语句)，小编现在分享给大家，供广大互联网技能从业者学习和参考。文章包含3193字，纯文字阅读大概需要5分钟。

内容图文

我已经调查了这个,但我找不到任何帮助我的东西(道歉,如果类似的东西的答案可以帮助我).我正在编写一个货币转换器,它遭受了大量的if,它看起来效率不高,我也无法想象它的可读性非常好,所以我想知道如何在这种情况下编写更有效的代码：

prompt = input("Input") #For currency, inputs should be written like "C(NUMBER)(CURRENCY TO CONVERT FROM)(CURRENCY TO CONVERT TO)" example "C1CPSP"

if prompt[0] == "C": #Looks at first letter and sees if it's "C". C = Currency Conversion
    #CP = Copper Piece, SP = Silver Piece, EP = Electrum Piece, GP = Gold Piece, PP = Platinum Piece
    ccint = int(''.join(list(filter(str.isdigit, prompt)))) # Converts Prompt to integer(Return string joined by str.(Filters out parameter(Gets digits (?), from prompt))))
    ccalpha = str(''.join(list(filter(str.isalpha, prompt)))) #Does the same thing as above expect with letters

    if ccalpha[1] == "C": #C as in start of CP
        acp = [ccint, ccint/10, ccint/50, ccint/100, ccint/1000] #Array of conversions. CP, SP, EP, GP, PP
        if ccalpha[3] == "C": #C as in start of CP
            print(acp[0]) #Prints out corresponding array conversion
        if ccalpha[3] == "S": #S as in start of SP, ETC. ETC.
            print(acp[1])
        if ccalpha[3] == "E":
            print(acp[2])
        if ccalpha[3] == "G":
            print(acp[3])
        if ccalpha[3] == "P":
            print(acp[4])
    if ccalpha[1] == "S":
        asp = [ccint*10, ccint, ccint/10, ccint/10, ccint/100]
        if ccalpha[3] == "C":
            print(asp[0])
        if ccalpha[3] == "S":
            print(asp[1])
        if ccalpha[3] == "E":
            print(asp[2])
        if ccalpha[3] == "G":
            print(asp[3])
        if ccalpha[3] == "P":
            print(asp[4])
    if ccalpha[1] == "E":
        aep = [ccint*50, ccint*5 ,ccint , ccint/2, ccint/20]
        if ccalpha[3] == "C":
            print(aep[0])
        if ccalpha[3] == "S":
            print(aep[1])
        if ccalpha[3] == "E":
            print(aep[2])
        if ccalpha[3] == "G":
            print(aep[3])
        if ccalpha[3] == "P":
            print(aep[4])
    if ccalpha[1] == "G":
        agp = [ccint*100, ccint*10, ccint*2, ccint, ccint/10]
        if ccalpha[3] == "C":
            print(agp[0])
        if ccalpha[3] == "S":
            print(agp[1])
        if ccalpha[3] == "E":
            print(agp[2])
        if ccalpha[3] == "G":
            print(agp[3])
        if ccalpha[3] == "P":
            print(agp[4])
    if ccalpha[1] == "P":
        app = [ccint*1000, ccint*100, ccint*20, ccint*10, ccint]
        if ccalpha[3] == "C":
            print(app[0])
        if ccalpha[3] == "S":
            print(app[1])
        if ccalpha[3] == "E":
            print(app[2])
        if ccalpha[3] == "G":
            print(app[3])
        if ccalpha[3] == "P":
            print(app[4])

解决方法:

您始终可以使用词典进行查找：

lookup = {'C': {'C': ccint, 'S': ccint/10, 'E': ccint/50, 'G': ccint/100, 'P': ccint/1000},
          'S': {'C': ccint*10, 'S': ccint, 'E': ccint/10, 'G': ccint/10, 'P': ccint/100},
          'E': {'C': ccint*50, 'S': ccint*5, 'E': ccint, 'G': ccint/2, 'P': ccint/20},
          'G': {'C': ccint*100, 'S': ccint*10, 'E': ccint*2, 'G': ccint, 'P': ccint/10},
          'P': {'C': ccint*1000, 'S': ccint*100, 'E': ccint*20, 'G': ccint*10, 'P': ccint}
         }

那么你所有的ifs大部分都包含在：

print(lookup[ccalpha[1]][ccalpha[3]])

但是可能包含其他字符吗？然后你需要引入一个后备：

try:
    print(lookup[ccalpha[1]][ccalpha[3]])
except KeyError:
    # Failed to find an entry for the characters:
    print(ccalpha[1], ccalpha[3], "combination wasn't found")

如上所述,它不是最有效的方式,因为它每次都计算每次转换(即使是不必要的转换).拥有基线可能更有效,例如P并保存因子：

lookup = {'C': 1000,
          'S': 100,
          'E': 50,
          'G': 10,
          'P': 1,
          }

# I hope I have them the right way around... :-)
print(ccint * lookup[ccalpha[3]] / lookup[ccalpha[1]])  

内容总结

以上是互联网集市为您收集整理的python – 更高效的代码(看似太多if语句)全部内容，希望文章能够帮你解决python – 更高效的代码(看似太多if语句)所遇到的程序开发问题。 如果觉得互联网集市技术教程内容还不错，欢迎将互联网集市网站推荐给程序员好友。

内容备注

版权声明：本文内容由互联网用户自发贡献，该文观点与技术仅代表作者本人。本站仅提供信息存储空间服务，不拥有所有权，不承担相关法律责任。如发现本站有涉嫌侵权/违法违规的内容， 请发送邮件至 gblab@vip.qq.com 举报，一经查实，本站将立刻删除。

内容手机端