Continuation--Basic type--array __ Regular expressions

=~ in the String class, is an overloaded operator used to match a string on the left with a regular expression on the right, to return the location of the match or nil in the RegExp class, and the "=~" operator is to match the string on the right with the regular expression on the left.

Sub and Sub. To match a string with an expression

Gsun and Gsub. is one of the most important methods of a string class, and the difference between a sub method: A sub handles only the first matching object, while gsub iterates through the entire string, modifying each object to which it matches.

Array

Definition: The definition of a standard by using the symbol box to select a series of data separated by commas. For example: arr=[1,2,3,4] Constructs an array definition from a class method. There are mainly "[]" and "new" for example: arr=array[1,2,3,4] or arr=array.new general qualifier to generate an array: arr=%w (1 2 3 4 5) Other ways: arr= "1 2 3". Split ()

Common methods self& array: Array with, returns the intersection of two arrays self | Array: Arrays or, returns the set of two arrays Self + array: Array Plus, returns the concatenation self.length of two arrays: Returns the length of an array. Self.size: Ditto. Self.empty?: To determine whether an array is empty self.clear: Empty the array self<<obj: Append elements to the array itself, return itself Self<=>array: array comparison, returns -1,0,1 Self.push (obj ): Appends the object to the last element of the array and returns itself. Self.unshift (obj): Appends an object to the first element of the array and returns itself. Self.shift: Returns the first element of the array and deletes it, returns nil Self.uniq if the array is empty, deletes the duplicate item inside the array, and returns a new string self.uniq!; Deletes the duplicate item inside the array, returning nil or itself Self.delete (obj): Removes the element from the array, deletes all if the element has duplicates, and returns nil Self.concat (array) If there is no such element in the array: appends the element to the array, returns itself Self.reverse: Reverses the array, produces a new array, and returns self.reverse!: Reverses the array and returns its own self[n]: Returns an element of the nth element in the array, which goes beyond the border to return nil Self.join (sepstr=$): Joins the array element with the set delimiter, returning a string Self.sort: Sorts the array, returning the new string. self.sort!: Sort the array, returning to its own self.to_s: exporting the array as a string

Find and assign values

The lookup method includes "[]", "include?" Index "method and so on. []: Returns an element or substring in an array that has three prototypes. Self[int]->obj or nil, self[start,length]->subarray or Nil.self[range]->subarray or nil include?: To determine whether an object is in an array Index: Find the position of the object in the array

Assignment: The method of assigning values is mainly "[]=".