Python - 确定集合中是否存在任何对象的优雅方法

Question

I have the following function - SomeFunction - which accepts a collection of incidents as a parameter ie IncidentsIn.

I then need to build a string - RetStr - depending on whether there are any details in IncidentsIn.

At the moment I am adding 1 to k if details exist and then testing the value of k to see if the string is updated with 'No Priorities reported' or not. This is not using Python elegance. Is there a better way?

def SomeFunction(IncidentsIn):

    RetStr = 'Incidents: '
    k = 0

    for z in (x for x in IncidentIn if x.Priority in ('1', '2', '3')):
        k += 1
        RetStr += 'Add incident detail to string'

    if k == 0:
        RetStr += 'No Priorities reported'

Answer 1

You could first get

 items = (x for x in ...)

and next use `len(items)

 if len(items): 
     RetStr += 'No Priorities reported'` 
 else:
     for z in items:
         RetStr += 'Add incident detail to string

Or you could create list with details and later check if it is not empty.

 items = (x for x in ...)

 details_str = []  # empty list

 for z in item:
     details_str.append( 'Add incident detail to string' )

 if details_str:
     RetStr = 'Incidents: ' + "".join(details_str)
 else:
     RetStr = 'Incidents: No Priorities reported'

Of course you could do the same with empty string

 items = (x for x in ...)

 details_str = ""  # empty string

 for z in item:
     details_str += 'Add incident detail to string' )

 if details_str:
     RetStr = 'Incidents: ' + details_str
 else:
     RetStr = 'Incidents: No Priorities reported'