PHP Learning Notes (a common method in JS)

Common methods in JS:

1. Date-time function (requires variable invocation):
var B = new Date (); Get current time
B.gettime ()//Get timestamp
B.getfullyear ()//Get Year
B.getmonth (+1); Get month
B.getdate ()//Get Day
B.gethours ()//Get Hours
B.getminutes ()//Get minutes
B.getseconds ()//Get the number of seconds
B.getday ()//Get the day of the week
B.getmilliseconds ()//Get milliseconds
Date ()//Get full date

2. Mathematical functions (called with math):
ABS (x) The absolute value of the return number.
Ceil (x) is rounded on the logarithm.
Floor (x) is rounded down with a logarithmic.
Round (x) rounds the number to the nearest integer.
Max (x, y) returns the highest value in X and Y.
Min (x, y) returns the lowest value in X and Y.
The POW (x, y) returns the y power of X.
SQRT (x) returns the square root of the number.
Random () returns an arbitrary number between 0 and 1. ****

String functions (called with variables):

IndexOf
Returns the index (from left to right) of the first occurrence of a substring in a string. If there is no match, returns-1.
var index1 = A.indexof ("L");
INDEX1 = 2

CharAt returns the character at the specified position.

var Get_char = A.charat (0);
Get_char = "H"

L Astindexof
Returns the index (right-to-left search) at the last occurrence of a substring in a string, or 1 if there are no matches.
var index1 = lastIndexOf (' l ');
INDEX1 = 3

Match
Checks if a string matches the contents of a regular expression, and returns null if there is a match.
var re = new RegExp (/^\w+$/);
var is_alpha1 = A.match (re);
IS_ALPHA1 = "Hello"
var is_alpha2 = B.match (re);
IS_ALPHA2 = null

Substring
Returns a substring of a string in which the incoming parameter is the starting and ending position.

var sub_string2 = a.substring (1,4);
Sub_string2 = "ell"

SUBSTR ********
Returns a substring of a string in which the incoming parameter is the starting position and length
var sub_string1 = a.substr (1);
Sub_string1 = "Ello"
var sub_string2 = a.substr (1,4);
Sub_string2 = "Ello"

Replace *******
Replace String, the first argument represents the replaced string, the second argument represents the replacement string
A.replace ("he", "AA")

Search
Performs a regular expression matching lookup. If the lookup succeeds, returns the matching index value in the string. otherwise returns-1.
var index1 = A.search (re);
index1 = 0
var index2 = B.search (re);
Index2 =-1

Split ******
A string is made into a string array by dividing the string into substrings.
var arr1 = A.split ("");
ARR1 = [H,e,l,l,o]

Length property *******
Returns the length of a string, which refers to the number of characters it contains.

toLowerCase
Turns the entire string into lowercase letters.
var lower_string = A.tolowercase ();
lower_string = "Hello"

toUpperCase
Turns the entire string into uppercase.
var upper_string = A.touppercase ();
upper_string = "HELLO"

PHP Learning Notes (a common method in JS)