python sql n00b tips snippets

python sql n00b snippets

python 
>>> import urllib2
>>> p = urllib2.urlopen("http://www.google.com")
>>> c = p.read()
>>> c
>>> dir(p)
>>> exx = p.geturl()
>>> exx
'http://www.google.com.tr/?gfe_rd=cr&ei=77OxVof4Hqyo8we8qoyADw'
>>> p.headers.items()
[('content-length', '19509'), ('x-xss-protection', '1; mode=block')]

>>> from xml.dom import minidom
>>> x = minidom.parseString("<mytag>contents<children><item>x1</item><item>x2</item></children></mytag>")
>>> x
<xml.dom.minidom.Document instance at 0x7fb8d0828200>
>>> x.childNodes[0].getElementsByTagName("children")[0].getElementsByTagName("item")[1].childNodes[0].nodeValue
u'x2'

>>> xmlNY = urllib2.urlopen("http://rss.nytimes.com/services/xml/rss/nyt/InternationalHome.xml").read()
>>> parsedFromNYXML = minidom.parseString(xmlNY)
>>> parsedFromNYXML = minidom.parseString(xmlNY)
>>> g3.getElementsByTagName("item").length
20
>>> len(g3.getElementsByTagName("item"))
20

>>> import json
>>> j= '{"xx": 12, "arr": [1,2,4.5]}'
>>> json.loads(j)

def total_ups():
    sum = 0
    j = json.loads(reddit_front)
    x = j.get("data").get("children")
    for c in x:
        sum += c.get("data").get("ups")
    return sum

print total_ups()


urllib2.urlopen('http://rss.nytimes.com/services/xml/rss/nyt/InternationalHome.xml')
proxy = urllib2.ProxyHandler({'http': 'user:pass@ip:port'})

# cache example
import time
# complex_computation() simulates a slow function. time.sleep(n) causes the
# program to pause for n seconds. In real life, this might be a call to a
# database, or a request to another web service.
def complex_computation(a, b):
    time.sleep(.5)
    return a + b

# QUIZ - Improve the cached_computation() function below so that it caches
# results after computing them for the first time so future calls are faster
cache = {}
def cached_computation(a, b):
    key = (a,b)
    if key in cache:
        return cache[key]
    else:
        tmp = complex_computation(a, b)
        cache[key] = tmp
    return tmp

# JS arr => list, tuple | JS obj => dict, set
# list, tuples ops compared to JS
a.length						len(l)
a.push(item)				l.append(item)
a.pop()							l.pop()
a.shift()						l.pop(0)
a.unshift(item)			l.insert(0, item)
a.slice(start, end)	l[start:end]
a.splice(start, howMany, [...])	l[start:end] = [...]


# sql
# ; always end with semicolon ;
id|genre|title|duration
xxx

select * from concessions where item = 'Popcorn';
select item, price, size from concessions where item = 'Popcorn' order by price desc;
insert into movies (genre, title) values ('Romance', 'Sweet November');
insert into movies (id, genre, title, duration) values (8, 'Comedy', 'Jackass', 123);
update movies set 'genre' = 'drama' where id = 5;
update movies set 'genre' = 'drama', duration = 55 where id = 5;
update movies set title = 'xxx' where id = 5 or id = 3;
delete from movies where id = 5;
create database FRESH DB;
drop database FRESH DB;
create table FRESH DB (col_name1 datatype, col_name2 datatype, col_name3 datatype);
create table movies (id int, title varchar(50), genre varchar(20), duration int);
drop table movies;
alter table dbnamexxx add column col_namexxx datatype;
alter table dbnamexxx drop column col_namexxx;