Android programmers learn PHP development (5)-Boolean scientific notation-PhpStorm

In addition to the following code, we also need to talk about floating point numbers. float is an approximate number. for example, in java or js, 0.1 is added 10 times, and the result is 1.0000001 instead of 1. In addition to the following code, we also need to talk about floating point numbers. float is an approximate number. for example, in java or js, 0.1 is added 10 times, and the result is 1.0000001 instead of 1.

 Int (0)} --- true $ bool13 = new Iwanghang; // print the result: object (Iwanghang) #1 (0) {}--- real class Iwanghang {}$ bool14 = ord ("hello world"); // print the result: int (104) --- true, ord () the function returns the ASCII value of the first character of the string. $ Bool15 = 1.2e3; // print the result: float (1200) --- true, equivalent to 1.2*(10 to the power of 3) $ bool16 = 7E-10 + 1; // print the result: float (1.0000000007) --- true, equivalent to 7*(10-10 power) plus 1 $ bool17 = 3E + 5; // print the result: float (300000) --- true, equivalent to 7*(10 to the power of-10) $ bool18 = 0.00000000006; // float (6.0E-11) --- true $ bool19 = 3E-3; // float (0.003) --- true, if the number is small, 0.003 is displayed normally. $ bool16 is too long. If no value is added, the scientific notation var_dump ($ bool) is displayed. // print the result: bool (true) echo"
"; Var_dump ($ bool2); // print the result: bool (false) echo"
"; Var_dump ($ bool3); // print the result: int (0) --- false if ($ bool3) {echo" --- true ";} else {echo "--- false" ;}; echo"
"; Var_dump ($ bool4); // print the result: float (0) --- false if ($ bool4) {echo" --- true ";} else {echo "--- false" ;}; echo"
"; Var_dump ($ bool5); // print the result: float (0) --- false if ($ bool5) {echo" --- true ";} else {echo "--- false" ;}; echo"
"; Var_dump ($ bool6); // print the result: string (0)" "--- false if ($ bool6) {echo" --- true ";} else {echo "--- false" ;}; echo"
"; Var_dump ($ bool7); // print the result: string (1)" "--- true if ($ bool7) {echo" --- true ";} else {echo "--- false" ;}; echo"
"; Var_dump ($ bool8); // print the result: string (1)" 0 "--- false if ($ bool8) {echo" --- true ";} else {echo "--- false" ;}; echo"
"; Var_dump ($ bool9); // print the result: string (3)" 0.0 "--- true if ($ bool9) {echo" --- true ";} else {echo "--- false" ;}; echo"
"; Var_dump ($ bool11); // print the result: array (0) {}--- false if ($ bool11) {echo" --- true ";} else {echo "--- false" ;}; echo"
"; Var_dump ($ bool12); // print the result: array (1) {[0] => int (0)} --- true if ($ bool12) {echo "--- true";} else {echo "--- false" ;}; echo"
"; Var_dump ($ bool13); // print the result: object (Iwanghang) #1 (0) {}--- true if ($ bool13) {echo" --- true ";} else {echo "--- false" ;}; echo"
"; Var_dump ($ bool14); // print the result: int (104) --- true if ($ bool14) {echo" --- true ";} else {echo "--- false" ;}; echo"
"; Var_dump ($ bool15); // print the result: float (1200) --- true if ($ bool15) {echo" --- true ";} else {echo "--- false" ;}; echo"
"; Var_dump ($ bool16); // print the result: float (1.0000000007) --- true if ($ bool16) {echo" --- true ";} else {echo "--- false" ;}; echo"
"; Var_dump ($ bool17); // print the result: float (300000) --- true if ($ bool17) {echo" --- true ";} else {echo "--- false" ;}; echo"
"; Var_dump ($ bool18); // print the result: float (6.0E-11) --- true if ($ bool18) {echo" --- true ";} else {echo "--- false" ;}; echo"
"; Var_dump ($ bool19); // print the result: float (0.003) --- true if ($ bool19) {echo" --- true ";} else {echo "--- false" ;}; echo"
";

The above is the content of PhpStorm, which is used by Android programmers to learn PHP development (5)-Boolean scientific notation. For more information, see PHP Chinese website (www.php1.cn )!