Basic Package Type
<Script>
// Basic Package Type
var STR = 'Andy' ;
the console.log (str.length);
// objects have properties and methods of complex data types have attributes and methods
// simple data types why length property it?
// Basic Package Type: data type is the simple packaging has become a complex data type
// (1) the simple data type is a complex data type packaging
var TEMP = new new String ( 'Andy' );
// (2) the temporary variable the value to the STR
STR = TEMP;
// (. 3) destruction of the temporary variable
TEMP = null ;
</ Script>
Immutability of strings
<Script>
// immutability string
var STR = 'Andy' ;
the console.log (STR);
STR = 'Red' ;
the console.log (STR);
// because our string immutable so do a lot of string concatenation
var STR = '' ;
for ( var I =. 1; I <= 1000000000; I ++ ) {
STR + = I;
}
the console.log (STR);
</ Script>
Returns the position of the character
<Script>
// String object to return the character position str.indexOf ( 'the character to find', [the starting position])
var STR = 'reform the revival of the floor, to the spring' ;
the console.log (STR .indexOf ( 'spring' ));
the console.log (str.indexOf ( 'spring', 3)); // back to find the start position of the index number 3 is
</ script>
Find the location and the number of strings "abcoefoxyozzopp" all appear o
<Script>
// search string position "abcoefoxyozzopp" all appear and the number o
// core algorithms: the first find the location of the first occurrence of a o
// then return results as long as indexOf is not -1 would continue in the future to find
/ / because indexOf only to find the first, so the back of the lookup, the current index must be incremented by one, thereby continuing to find
var STR = "oabcoefoxyozzopp" ;
var index = str.indexOf ( 'O' );
var NUM = 0 ;
// the console.log (index);
the while (index == -1! ) {
the console.log (index);
NUM ++ ;
index = str.indexOf ( 'O', + index. 1 );
}
the console.log ('it is the number of occurrence o:' + NUM);
// homework [ 'red', 'blue' , 'red', 'green', 'pink', 'red'], and the number of required positions appear red
</ script>
Returns the character (Key) based on the location
<Script>
// The position of the character to return
// 1. the charAt (index) Returns the character based on the position
var STR = 'Andy' ;
the console.log (str.charAt ( . 3 ));
// traverse all characters
for ( var I 0 =; I <str.length; I ++ ) {
the console.log (str.charAt (I));
}
// 2. the charCodeAt (index) returns the ASCII value of the character object corresponding to the index number: determining the key pressed by the user
the console.log (str.charCodeAt (0)); // 97
// 3. STR [index] the H5 added
the console.log (STR [0]); // a
</ Script>
Determining the largest number of characters of a string 'abcoefoxyozzopp' appears in and count the number thereof.
<Script>
// there is an object to determine whether the object has the attribute [ 'attribute name']
var O = {
Age: 18 is
}
IF (O [ 'Sex' ]) {
the console.log ( 'which has the property' ) ;
} the else {
the console.log ( 'the attribute is not' );
}
// C
// OA =. 1
// OB. 1 =
// OC =. 1
// OO =. 4
// core algorithms: using the charAt () iterates through the string
// each character is stored to the object, if the object does not have this property, it is one, if it exists +1
// traverse the object, to obtain the maximum value and the character
var= STR 'abcoefoxyozzopp' ;
var O = {};
for ( var I = 0; I <str.length; I ++ ) {
var chars = str.charAt (I); // chars every character of the string
IF ( O [chars]) { // O [chars] is obtained attribute value
O [chars] ++ ;
} the else {
O [chars] =. 1 ;
}
}
the console.log (O);
// 2. traverse the object
var 0 = max ;
var CH = '' ;
for ( var K in O) {
// K is obtained property name
// O [K] obtained is the attribute value
IF (O [K]> max) {
max = O [K];
CH = K;
}
}
Console .log (max);
the console.log ( 'character is the most' + CH);
</ Script>
<Script>
// String Operation
// 1. the concat ( 'string 1', 'string 2' ....)
var STR = 'Andy' ;
the console.log (str.concat ( 'Red' ) );
// 2. substr ( 'starting position taken' ', taken several characters');
var str1 = 'reform the revival floor' ;
the console.log (str1.substr ( 2, 2)); / / second from a 2 2 2 several start of the second is to take the number of characters of the index
</ script>
Alternatively string segmentation and
<Script>
// 1. Replace replacement character ( 'character is replaced by a', 'character is replaced') only replaces the first character
var STR = 'andyandy' ;
the console.log (str.replace ( 'A ',' B ' ));
// a string' abcoefoxyozzopp 'which requires to replace all o *
var str1 =' abcoefoxyozzopp ' ;
the while (str1.indexOf ('! o ') == -1 ) {
str1 = str1.replace ( 'O', '*' );
}
the console.log (str1);
// 2. Split into an array of characters ( 'separator') join the front we have learned the array to a string
var = str2 'Red, Pink, Blue' ;
Console.log(str2.split(','));
var str3 = 'red&pink&blue';
console.log(str3.split('&'));
</script>
