Python tips

1, input and raw_input

1.1, treat input as string? or meaningful object

 

>>> raw_input_A = raw_input("raw_input: ")

raw_input: PythonTab.com

>>> print raw_input_A 

PythonTab.com

>>> input_A = input("Input: ")

Input: PythonTab.com

Traceback (most recent call last):

  File "<stdin>", line 1, in <module>

  File "<string>", line 1, in <module>

NameError: name 'PythonTab' is not defined

>>> 

>>> input_A = input("Input: ")

Input: "PythonTab.com"

>>> print input_A

PythonTab.com

>>>

 

1.2, data type

 

>>> raw_input_B = raw_input("raw_input: ")

raw_input: 2015

>>> type(raw_input_B)

<type 'str'>

>>> input_B = input("input: ")

input: 2015

>>> type(input_B)

<type 'int'>

 

 2, spider issue1

 

------- issue:　　class DmozSpider(scrapy.Spider):
AttributeError: 'module' object has no attribute 'Spider'

 

-------solution

 

sudo apt-get install scrapy　　　　　　// version is too low

sudo apt-get install python-pip

sudo pip install scrapy　　　　　　　　　　//no head file for scrapy

sudo apt-get install python-dev
sudo pip install scrapy --upgrade

 

3, Spider issue2

 

2015-12-07 15:33:21 [boto] ERROR: Caught exception reading instance data

 

解决方法------http://blog.csdn.net/liyuetao680/article/details/48313313

 

在setting.py中禁用s3 download就可以了 , say .................DOWNLOAD_HANDLERS = {'s3':None,}...........must be lowcase and :

 

another way is :      

 

from scrapy import optional_features

optional_features.remove('boto')

 

4, Spider

 

http://www.myexception.cn/web/1646523.html  　　　　　　　　//contains ........scrapy crawl dmoz -o items.json -t json 

http://doc.scrapy.org/en/latest/intro/tutorial.html

http://blog.csdn.net/pleasecallmewhy/article/details/19642329

 

5， advanced data type(structure)

http://liuzhichao.com/p/1645.html

list,tuple,Dictionary,set,file

 

6,

>>> dict = { 1 : 2, 'a' : 'b', 'hello' : 'world' }
>>> dict.values()
['b', 2, 'world']
>>> dict.keys()
['a', 1, 'hello']
>>> dict.items()
[('a', 'b'), (1, 2), ('hello', 'world')]
>>>