statements and return within a lambda expression lambda

Question

In C# I'm trying to verify if a buss full of passengers is ready to go by verifying the passengers payments:

bool busReadyToGo = true;
passengers.Any(p => p.paymentStatus == PaymentRegistryEnum.NotPaid ?  busReadyToGo = false; return busReadyToGo; : continue; );

So this should check all the passengers payment status, if it encounters one passenger that hasn't paid then it stops right there and returns busReadytoGo = false. otherwise it continues iterating/filtering passengers, which means it will later return true if a passenger hasn't paid.

Not sure if this is the right way to do this within the Linq/lambda expression, because I keep getting syntax errors.

Steve · Accepted Answer · 2019-04-30 17:49:28Z

2

Any already stops its enumeration when it meets the first element that returns true in the lambda expression. You just need to get the result from Any

busReadyToGo = !passengers.Any(p => p.paymentStatus == PaymentRegistryEnum.NotPaid);

If you look at the Remarks section in docs you can read

The enumeration of source is stopped as soon as the result can be determined.

answered Apr 30, 2019 at 17:49

Steve

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4 Comments

Tlink Over a year ago

What does it return? a bool? Do I need to handle null?

Steve Over a year ago

Yes, it returns a bool, No there is no null to handle here

Tlink Over a year ago

even if I pass an empty List?

Steve Over a year ago

Yes, if you use an empty list then the result will be false

sekky · Accepted Answer · 2019-04-30 17:49:29Z

2

The method .Any will already return a bool value. There is no need to include an if-Statement in the expression. This should do just fine:

bool busReadyToGo = !passengers.Any(p => p.paymentStatus == PaymentRegistryEnum.NotPaid)

answered Apr 30, 2019 at 17:49

sekky

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