Sorting data using std::map or std::multimap
Happy New Year. Hope everyone is ok. I have not been here for a while.
I have some contact lens data I'm trying to sort. I have some sort rules are static (hard-coded) followed by other rules form 'normal' rules
Here are the requirements:
First sort by Company and Product is a static order (hard-coded, non alphbetic)
Sample
o Company ProductName
- Ciba 1. Focus, 2. AirOptics, 3. Dailies, 4. then alphabetical.
- Bausch & Lomb 1. PureVision, 2. LiquidEye, 3. Softlens then alphabetical.
Followed by Package size decending (80, 30 ...)
Followed by Base Curve decending (8.6, 8,0 ...)
Followed by Sphere decending (-0.5, 0.0, 1.0 ...)
In the end the result might look like the following
Sample data
CO PR PS BC Sp
-------------------------------
Ciba Focus 10 8.6 0.00
Ciba Focus 20 8.6 -0.25
Ciba Focus 20 8.6 -0.10
Ciba Focus 20 8.6 +0.25
Ciba Air 10 8.6 -0.25
Ciba Air 10 8.6 -0.10
Ciba Air 20 8.1 -0.25
Ciba Air 20 8.1 -0.10
Ciba Air 20 8.1 0.00
Ciba Air 20 8.6 +0.25
Ciba Air 20 8.6 +0.40
The data is contained in a struct with other data. The stuct is used in a map with a key. I am building a key to sort for the static requirments such as below.
The key contains a prefix at the front of the key to force the static sort (non alphabetical), followed by a suffix to make the key unique. Sample key: "1_1_Ciba_Focus Monthlys_4"
My plan to sort the other requirments is to take each of the other requirments (PackageSize, Base Curve and Sphere) and sort them against the previous element with the key.
Since I will be sorting the following agaist the Package Size (10, 20 ...) - maybe I should be using the multimap, as it might be easter to sort this stuff without having the unique ID at the end of key ??
With the key of "1_1_Ciba Focus" I would sort on the PackSize and then set the key to produce the correct sort
start: (std::multimap)
key: 1_1_Ciba Focus"
Sample data
CO PR Key
-------------------------------
Ciba Focus 1_1_Ciba Focus
Ciba Focus 1_1_Ciba Focus
Ciba Focus 1_1_Ciba Focus
Ciba Focus 1_1_Ciba Focus
Sample data
CO PR PS Key
-------------------------------
Ciba Focus 10 1_1_1_Ciba Focus
Ciba Focus 20 1_1_2_Ciba Focus
Ciba Focus 20 1_1_2_Ciba Focus
Ciba Focus 20 1_1_2_Ciba开发者_高级运维 Focus
Thanks, Chris chris@macgowan.com
You can write a comparison functor that can take into account any number of criteria. The idea is to start at the most significant criterion, then go down the list only when the upper levels are equal.
struct LensCompare
{
bool operator()(const Data & left, const Data & right)
{
if (left.key < right.key)
return true;
else if (right.key < left.key)
return false;
if (left.PR < right.PR)
return false; // for descending order return "false" when less than
else if (right.PR < left.PR)
return true;
if (left.BC < right.BC)
return false;
else if (right.BC < left.BC)
return true;
return right.Sp < left.Sp;
}
};
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