iterable api

To implement a class that can be used with a foreach loop, you must implement Iterable, which overrides a Iterator method, which returns a iteratorThe code is as follows:public class Itertest implements IterableStores the contents of the array private object[] Obj=new object[1];//record the number of elements added to the private int size;Records the current element's subscript private int current=0;//add element public void Add (String str) {Determ

This function functions as a function ,iterable Each item of the object as a parameter, and then calculates the output iteration sub - iterator. If function object functions can enter multiple parameters, then it can be followed by multiple objects that can be iterated. When multiple iterations of an object, the shortest object is judged by the result of the run. Example:#map () x = Range (Ten) print (list (map (hex, x)) Print (list (map (lambda y:y

This function is implemented to sort the iterable of an iterative object . The optional parameter key is a function of the comparison key;Reverse is a Boolean value that indicates whether to reverse-arrange the items in the object. Example:#sorted () print (sorted ([5, 2, 3, 1, 4])) print (sorted ({1: ' D ', 2: ' B ', 3: ' B ', 4: ' E ', 5: ' A '}, reverse = True)) print (sorted ("This was a test string from Andrew". Split (), Key=str.lower)) Student_

This function returns a frozen collection. The so-called freeze is that this collection can no longer add or remove elements from any collection. So the difference between set and set is that set is the element that can be added or deleted, and frozenset not. The main function of Frozenset is fast, which is realized by using hash algorithm. The parameter iterable is an object that represents an iteration, such as a list, a dictionary, a tuple, and

Returns trueif all elements of an object that can iterate are true if there is one element, otherwise Falseis returned. Or the iterator object is empty and also returns False. This function is mainly used to determine whether the list, tuple, dictionary and other objects have elements of True, increase the speed of computation, the equivalent code is as follows:def any (iterable):For element in iterable:If element:Return TrueReturn FalseExample:#any

There is a iterator () method in the list, set, queue, which is defined in the collection interface before JDK5 appears, and the list, set, and queue are inherited from Collecition. So they all have the iterator () method. The iterator () method returns the action object for the Java.util.Iterator interface, which includes all the objects that the collection collects, and you can use iterator Hasnext () to see if there is a next object, if any, You can use next () to get the next object. After

Package Java.lang;Import Java.util.Iterator;Public interface Iterable Iterator}Iterable is located in the Java.lang package, which holds a iterator referencePackage java.util;Public interface Iterator Boolean hasnext (); E next (); void Remove ();}Iterator is also an interface that contains three methods, Hasnext, Next, remove Public Interface extends iterableJava.util.Collection inherits from J

Python error TypeError: 'nonetype 'object is not iterable solution, typeerroriterable Python error TypeError: 'nonetype 'object is not iterable Solution TypeError: 'nonetype 'object is not iterable. This error message generally occurs when None is assigned to multiple values. Def myprocess (): a = B if! = B: return True, value; flag, val = myprocess () In the

it is removed, then the cursor value must be reduced by one. In fact, the implementation of the iterator here is basically covered by abstractlist subclasses, such as Linkedlist,arraylist. The former does not support random access must not use the index value as the implementation of the acquisition element, otherwise the efficiency of the iterator is too low.Listiterator (extends IteratorIn addition to inheriting the Iterable interface, the list int

Python standard library: built-in functions all (iterable) and pythoniterable If all the elements of an object that can be iterated are not empty (or empty iteration object), True is returned. This function is mainly used to determine whether objects such as lists, tuples, and dictionaries are empty elements. For example, a list with 10000 elements is provided. If this function is not provided, it must be implemented through loops, the computing speed

1 iterable Objects that implement this interface are allowed to be the targets of the "foreach" statement.From the code point of view, iterable only wraps an iterator After 1.5, foreach and collections all implement the iterable 2. Dynamic PlanningThe basic idea of dynamic planning is to divide the problem to be solved into several subproblems and solve them in s

List (set (map (lambda tp_id:tp_id If not (' # ' in tp_id) and Len (Tp_id.strip (). replace (' \ n ', ')) > 0else None, open (' Tp_list.txt '). ReadLines ()). Sort ()))To practice the map, think of a loop as a line of code.There is a problem with the structure running program: TypeError: ' Nonetype ' object is not iterable.Find a half-day error (write a line of code at this time is really dead)Found to be the sort problem, the list's member method sort () Sorts a list (which changes the list) bu

1.Comparable Interface Description: Can be compared (sortable)Example: sequencing by the Y attribute of MyClassClass MyClass implements comparable2.Comparator Interface Description: Iterator, the parameter of the sort functionExample: Sorting by the X attribute of MyClassClass myclass{public int x; public int y; Public MyClass (int x,int y) { this.x=x; this.y=y; } @Override public String toString () { return x+ "@" +Y; }} Class Mycomparator implements co

Python standard library: built-in function enumerate (iterable, start = 0), enumerateiterable This function converts an Iterated object to an enumerated object. Iterable is an iterative parameter, such as a list, array, or dictionary object. start is the start value of enumeration. The default value is from 0. The implementation principle of this function is as follows: Get a value from the method _ next _

This function converts an iterative object to an enumeration object. iterable is an iterative parameter, such as a list, an array, a dictionary, and other objects; Start is the starting value of the enumeration, which is the default from 0 start. The principle of this function is to obtain a value from the method __next__ () of the iterative object, and then Start counting the parameter start, adding 1 per item , a tuple is generated to return. Thi