如何通过关键字字典传递可选参数

时间:2020-07-07 08:37:26

标签: python dictionary parameter-passing

我正在研究一种检查数据文件格式的脚本(例如csv)

我在每个字段上应用各种规则:最大长度,空白字段,值边界,正则表达式以匹配(检查有效电子邮件)等...

这些规则在字典中(每个collum有一个):

#column 1 : integer from 1 to 99, except 10
{
"minval":1,
"forbiddenvals": [10,15],
"maxval":100
}

我的函数定义如下:

def vercol(data,
           empty=False,isadate = None,
           minlen=None,maxlen=None,
           minval=None,maxval=None,
           allowedvals=[],forbiddenvals=[],
           regex =None):
    """
    Verify if the field 'data' checks the rules
    
    Parameters /Rules
    ----------     
    empty : Boolean, optional
        set to True if empty field is accepted. The default is False.      
    minlen : integer, optional
        If set, minimum length for the field.    
    maxlen : integer, optional
        If set, maximum length for the field.       
    forbidenvals : List, optional
        List of rejected values.
    (...)

    Returns
    -------
    True if all the rules are met. 
    "xError" if a test failled, where x depend of the wich test failed FIRST
    """
    
    if data == "":
        return True if empty else "EmptyFieldError" 
    if minlen and len(data) < int(minlen):
        return "MinLengthError"
    ....
    other rules
    ....
    return True

当我正常调用参数时,该函数无法正常工作:

我想做的就是通过这样的字典:

rules = {
    "minval":1,
    "forbiddenvals": [10,15],
    "maxval":100
    }
result = vercol(field, rules)
#foo

问题:它不起作用,尽管存在于字典中,参数仅使用其默认值。

#works fine
vercol('abcdefghi', maxlen=4) #return "MaxLenError"
vercol('', maxlen=4) #return "EmptyFieldError"
vercol('', empty=True) #return True

#problem 
rule = {"maxlen":4,"empty":False}
vercol('',rule) #retuns True , expected : "EmptyFieldError"
vercol('abcdefgh',rule) #retuns True , expected : "MaxLenError"

有解决这个问题的线索吗?

1 个答案:

答案 0 :(得分:0)

您必须使用**解开字典。尝试

rules = {
    "minval":1,
    "forbiddenvals": [10,15],
    "maxval":100
    }
result = vercol(field, **rules)
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