怪女孩‧蛻變中

●　Branching

　　making a decision to take one path or another.

●　Conditions

　　Simple Condition: only one condition
　　Compound Condition: the combination of two or more conditions

●　Logical Operator

　　◎　" not " Logical Operator

　　　　　not True = False
　　　　　not False = True

　　◎　" and " Logical Operator

　　　　　True and True = True
　　　　　True and False = False
　　　　　False and True = False
　　　　　False and False = False

　　Note: " and " can connect as much as conditions we need,
　　　　　but as long as there's one False condition,
　　　　　the compound condition is False

　　◎　" or " Logical Operator

　　　　　True or True = True
　　　　　True or False = True
　　　　　False or True = True
　　　　　False or False = False

　　Note:  " or " can connect as much as conditions we need,
　　　　　but as long as there's one True condition,
　　　　　the compound condition is True

●　Using " in " Operator

　　　Uses in conditon statements

　　　Input:
　　　　print "e" in "this is a test message"
　　　　print "ess" in "this is a test message"

　　　Output:
　　　　True
　　　　True

●　If, elif and else

　　if <condition> :
　　　　<statement>

　　elif <condition> :
　　　　<statement>

　　．．．

　　elif <condition> :
　　　　<statement>

　　else:
　　　　<statement>

　　Note:
　　　Each consecutive lines of code is called a " BLOCK ".
　　　Only one block will be executed.
　　　If there's more then one condition is TRUE,
　　　the block of the first true condition will be executed.

●　while Loop

　　while <condition> :
　　　　<statement>

　　Note: While the condition is TRUE, the code will be executed repeatedly

●　Comparison Operators

　　　==　equal to
　　　!=　 not equal to
　　　>　  greater then
　　　<　  less then
　　　>=　greater then or equal to
　　　<=　less then or equal to

●　International Infinite Loop, break and continue

　　◎　Input:
　　　　　count = 0
　　　　　while True:
　　　　　　count += 1

　　　　　　# end loop if count is greater then 7.
　　　　　　if count > 7:
　　　　　　　break

　　　　　　# skip 2
　　　　　　if count == 2:
　　　　　　　continue

　　　　　　print count

　　◎　Output:

　　　　　1
　　　　　3
　　　　　4
　　　　　5
　　　　　6
　　　　　7

　　　Note:
　　　The condition is always true, so this is a international infinite loop.
　　　When the code hits " continue ", the loop skip the rest of the codes
　　　and starts from the first line of the block.
　　　When the code hits " break ", the loop ended.

●　for Loop

　　for < i > in <main squence> :
　　　　<statement>

　　Note: A for loop repeats its loop body
　　　　　for each element of the sequesce.
　　　　　In this case, < i > is the varible
　　　　　that represents the elements in the sequence
　　　　　and <main squence> is the sequence.