Question about itertools module

[Huan Wang]

Hi everyone,

I am trying to use the itertools module following the Python documentation, but I got some questions about it.

The Python documentation (https://docs.python.org/2/library/itertools.html ) shows some examples like: 

chain('ABC', 'DEF')      --> A B C D E F

imap(pow,(2,3,10), (5,2,3)) --> 32 9 1000

However, the results are not the same as shown in the website. 

The version of Python I am running is 2.7.9,  and my codes are:

>>> import itertools

>>> itertools.chain('ABC', 'DEF')

<itertools.chain object at 0x0000000002A4B390>

>>> a = itertools.chain('ABC', 'DEF')

>>> a

<itertools.chain object at 0x0000000002A4B2E8>

>>> print a

<itertools.chain object at 0x0000000002A4B2E8>

>>> itertools.imap(pow, (2,3,10),(5,2,3))

<itertools.imap object at 0x0000000002A4B198>

>>> b = itertools.imap(pow, (2,3,10), (5,2,3))

>>> b

<itertools.imap object at 0x0000000002A4B240>

>>> print b

<itertools.imap object at 0x0000000002A4B240>

>>> 

I do not know why the outputs would not be able to print as   'A B C D E F' and  32 9 100.

Could someone help me to understand it? 

Cheers,

Huan

.

[Huan Wang]

Hi, 

I finally found the way to show the elements of my case in the question I asked.

The itertools module created an object NOT a list as shown in the returned information in Python IDE, like

<itertools.chain object at 0x0000000002A4B390> or <itertools.imap object at 0x0000000002A4B240>

To "print" the elements in the object, I should use for loop to go through it, like 

>>> import itertools

>>> a = itertools.chain('ABC', 'DEF')

>>> for i in a:

............print i

A

B

C

C

D

E

>>> b = itertools.imap(pow, (2,3,10), (5,2,3))

>>> for j in b:

...........print j

32

9

64

>>>

Huan

..

在 2015年3月24日星期二 UTC+2上午12:20:15，Huan Wang写道：