Difference between revisions of "If"
m
→Combining Comparisons
imported>HawkFest |
imported>HawkFest |
||
| Line 76: | Line 76: | ||
* However, this is not the case here: '''OR ("||") has a higher precedence than AND ("&&")''':<pre>if myVar1 == 1 && myVar2 == 1 || myVar2 == 5</pre>is equivalent to<pre>if myVar1 == 1 && (myVar2 == 1 || myVar2 == 5)</pre>This is true when MyVar1 = 1 AND myVar2 is either 1 or 5.<BR><BR>If you want the "&&" comparision operator to be evaluated first, you have to include that part in parentheses. In this case: <pre>if (myVar1 == 1 && myVar2 == 1) || myVar2 == 5</pre>is true when either myVar2 is 5 OR both, myVar1 and myVar2 are 1. | * However, this is not the case here: '''OR ("||") has a higher precedence than AND ("&&")''':<pre>if myVar1 == 1 && myVar2 == 1 || myVar2 == 5</pre>is equivalent to<pre>if myVar1 == 1 && (myVar2 == 1 || myVar2 == 5)</pre>This is true when MyVar1 = 1 AND myVar2 is either 1 or 5.<BR><BR>If you want the "&&" comparision operator to be evaluated first, you have to include that part in parentheses. In this case: <pre>if (myVar1 == 1 && myVar2 == 1) || myVar2 == 5</pre>is true when either myVar2 is 5 OR both, myVar1 and myVar2 are 1. | ||
The later also explains why one has to be very careful in positioning conditions in a [http://cs.elderscrolls.com/constwiki/index.php?title=Category:Conditions#The_Condition_List condition list] of an editor item: for the CS/OB's engine, OR has order preference, has precedence over AND. For example, the condition items (A AND B OR C AND D) are evaluated as (A AND (B OR C) AND D), and not (( A AND B) OR (C AND D)), as opposed to common operator notation for most languages. In general, we call this an ''inversed'' or ''negative'' notation. '''Always keep the later in mind when [http://en.wikipedia.org/wiki/Boolean_algebra_%28logic%29#Basic_operations applying boolean algebra] for evaluating some given expression when scripting''', as standard operator notations will lead you to errors. | The later also explains why one has to be very careful in positioning conditions in a [http://cs.elderscrolls.com/constwiki/index.php?title=Category:Conditions#The_Condition_List condition list] of an editor item: for the CS/OB's engine, OR has order preference, ''has precedence'' over AND. For example, the condition items (A AND B OR C AND D) are evaluated as (A AND (B OR C) AND D), and not (( A AND B) OR (C AND D)), as opposed to common operator notation for most languages. In general, we call this an ''inversed'' or ''negative'' notation. '''Always keep the later in mind when [http://en.wikipedia.org/wiki/Boolean_algebra_%28logic%29#Basic_operations applying boolean algebra] for evaluating some given expression when scripting''', as standard operator notations will lead you to errors. | ||