부울 true/false 및 문자열 'true'/'false&
풀어 주다: 2016-07-25 09:11:18
Booleans are used to represent the concepts of true and false.
They are most often used for testing if a statement is true or false and
they'll play a bigger role when we discuss logical expressions.Note that there is a difference between
boolean true/false and the strings "true"/"false".
-
- Booleans and NULL
-
-
- /* Booleans are used to represent the concepts of true and false.
- They are most often used for testing if a statement is true or false and
- they'll play a bigger role when we discuss logical expressions.
- Note that there is a difference between
- boolean true/false and the strings "true"/"false".
- */
- $bool1 = true;
- $bool2 = false;
-
- // When booleans are displayed, PHP will attempt to convert them into a string
- // You'll get either "1"/"0" or "1"/"" instead of true/false
- ?>
- $bool1:
- $bool2:
-
- /* NULL is used to represent the concept of nothing or the state of being empty
- In the below example three variable have been set,
- then boolean tests are performed and the results are output as a string
- */
- $var1 = 3;
- $var2 = "cat";
- $var4 = NULL;
-
- // isset tests whether a variable has been set
- // It returns true or false as a result of the test.
- ?>
- $var1 is set:
- $var2 is set:
- $var3 is set:
-
- $var1 is set:
- $var2 is set:
- $var3 is set:
-
-
- $var1 empty:
- $var4 empty:
-
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