Lua關係運算子範例 - tw511教學網

下表顯示了Lua語言支援的所有關係運算子。假設變數A=10，變數B=20，然後 -

運算子	描述	範例
`==`	檢查兩個運算元的值是否相等，如果相等，則條件變為真。	`(A == B)`結果為`false`
`~=`	檢查兩個運算元的值是否相等，如果值不相等則條件變為`true`。	`(A ~= B)`結果為`true`
`>`	檢查左運算元的值是否大於右運算元的值，如果是，則條件變為`true`。	`(A > B)`結果為`false`
`<`	檢查左運算元的值是否小於右運算元的值，如果是，則條件變為`true`。	`(A < B)`結果為`true`
`>=`	檢查左運算元的值是否大於或等於右運算元的值，如果是，則條件變為`true`。	`(A >= B)`結果為`false`
`<=`	檢查左運算元的值是否小於或等於右運算元的值，如果是，則條件變為`true`。	`(A <= B)`結果為`true`

範例

嘗試以下範例來了解Lua程式設計語言中可用的所有關係運算子 -

a = 21
b = 10

if( a == b )
then
   print("Line 1 - a is equal to b" )
else
   print("Line 1 - a is not equal to b" )
end

if( a ~= b )
then
   print("Line 2 - a is not equal to b" )
else
   print("Line 2 - a is equal to b" )
end

if ( a < b )
then
   print("Line 3 - a is less than b" )
else
   print("Line 3 - a is not less than b" )
end

if ( a > b ) 
then
   print("Line 4 - a is greater than b" )
else
   print("Line 5 - a is not greater than b" )
end

-- Lets change value of a and b
a = 5
b = 20

if ( a <= b ) 
then
   print("Line 5 - a is either less than or equal to  b" )
end

if ( b >= a ) 
then
   print("Line 6 - b is either greater than  or equal to b" )
end

當構建並執行上述程式時，它會產生以下結果 -

Line 1 - a is not equal to b
Line 2 - a is not equal to b
Line 3 - a is not less than b
Line 4 - a is greater than b
Line 5 - a is either less than or equal to  b
Line 6 - b is either greater than  or equal to b