A brief analysis of Python iterator examples _python

This article illustrates the simple use of Python iterators and share them for your reference. The specific analysis is as follows:

A builder expression is an iterator that is used to generate sequence parameters when a function is called

The generator object can be traversed or transformed into a list (or data structure such as a tuple), but it cannot be sliced (slicing). When the unique argument of a function is an iterative sequence, you can remove the parentheses at both ends of the generator expression and write more elegant code:------------->

>>>> sum (i for I in Xrange ())
 45

Sum declaration:

Sum (iterable[, start))
Sums start and the items of a iterable from left to right and returns the total. Start defaults to 0. The iterable ' s items are normally numbers, and are not allowed to be strings. The fast, correct way to concatenate a sequence of strings are by calling '. Join (Sequence). Note This sum (range (n), m) is equivalent to reduce (Operator.add, range (n), m) to add floating point values with extended p Recision, Math.fsum ().

Parameters require passing in an iterative sequence, and we pass in a generator object that is perfectly implemented.

Note that the following code is distinguished:

The J above is the generator type, and the following J is the list type:

j = (I for I in range (a)) print 
J,type (j) 
print ' * ' *70 
 
j = [I for I in Range (Ten)] 
print J,type (j) 

Results:

<generator object <genexpr> at 0x01cb1a30> <type ' generator ' >
********************************
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9] <type ' list ' >

I hope this article will help you with your study of Python programming.