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Linux kernel Magic SysRq Key

Kernel Panic了就有用了

The magic SysRq key is a key combination in the Linux kernel which allows the user to perform various low level commands regardless[......]

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HTML的Cache-control详解【转载】

网页的缓存是由HTTP消息头中的“Cache-control”来控制的，常见的取值有private、no-cache、max-age、must-revalidate等，默认为private。其作用根据不同的重新浏览方式分为以下几种情况：
（1）打开新窗口
如果指定cache-control的值[......]

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Python的print格式化输出还支持‘字符串’精度控制

1.格式化输出整数

strHello = "the length of (%s) is %d" %('Hello World',len('Hello World'))
print strHello
#输出果：the length of (Hello World) is 11

strHello = "the length of (%s) is %d" %('Hello World',len('Hello World'))

print strHello

#输出果：the length of (Hello World) is 11

2.格式化输出16制整数

#%x --- hex 十六进制
#%d --- dec 十进制
#%d --- oct 八进制

nHex = 0x20
print "nHex = %x,nDec = %d,nOct = %o" %(nHex,nHex,nHex)
#输出结果：nHex = 20,nDec = 32,nOct = 40
#使用整数的各个制打印同一个数

nHex = 0x20

print "nHex = %x,nDec = %d,nOct = %o" %(nHex,nHex,nHex)

#输出结果：nHex = 20,nDec = 32,nOct = 40

#使用整数的各个制打印同一个数

3.[......]

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Python实现的Google simhash算法

#!/usr/bin/env python
# -*- coding=utf-8 -*-

# Implementation of Charikar simhashes in Python
# See: http://dsrg.mff.cuni.cz/~holub/sw/shash/#a1

class simhash():
    def __init__(self, tokens='', hashbits=128):
        self.hashbits = hashbits
        self.hash = self.simhash(tokens)

    def __str__(self):
        return str(self.hash)

    def __long__(self):
        return long(self.hash)

    def __float__(self):
        return float(self.hash)

    def simhash(self, tokens):
        # Returns a Charikar simhash with appropriate bitlength
        v = [0]*self.hashbits

        for t in [self._string_hash(x) for x in tokens]:
            bitmask = 0
            #print (t)
            for i in range(self.hashbits):
                bitmask = 1 << i
                #print(t,bitmask, t & bitmask)
                if t & bitmask:
                    v[i] += 1 #查看当前bit位是否为1，是的话则将该位+1
                else:
                    v[i] += -1 #否则得话，该位减1

        fingerprint = 0
        for i in range(self.hashbits):
            if v[i] >= 0:
                fingerprint += 1 << i
#整个文档的fingerprint为最终各个位大于等于0的位的和
        return fingerprint

    def _string_hash(self, v):
        # A variable-length version of Python's builtin hash
        if v == "":
            return 0
        else:
            x = ord(v[0])<<7
            m = 1000003
            mask = 2**self.hashbits-1
            for c in v:
                x = ((x*m)^ord(c)) & mask
            x ^= len(v)
            if x == -1:
                x = -2
            return x

    def hamming_distance(self, other_hash):
        x = (self.hash ^ other_hash.hash) & ((1 << self.hashbits) - 1)
        tot = 0
        while x:
            tot += 1
            x &= x-1
        return tot

    def similarity(self, other_hash):
        a = float(self.hash)
        b = float(other_hash)
        if a>b: return b/a
        return a/b

if __name__ == '__main__':
    #看看哪些东西google最看重？标点？
    s = '看看哪些东西google最看重？标点？'
    hash1 =simhash(s.split())
    #print("0x%x" % hash1)
    #print ("%s\t0x%x" % (s, hash1))

    s = '看看哪些东西google最看重！标点！'
    hash2 = simhash(s.split())
    #print ("%s\t[simhash = 0x%x]" % (s, hash2))

    print '%f%% percent similarity on hash' %(100*(hash1.similarity(hash2)))
    print hash1.hamming_distance(hash2),"bits differ out of", hash1.hashbits

#!/usr/bin/env python

# -*- coding=utf-8 -*-

# Implementation of Charikar simhashes in Python

# See: http://dsrg.mff.cuni.cz/~holub/sw/shash/#a1

class simhash():

def __init__(self, tokens='', hashbits=128):

self.hashbits = hashbits

self.hash = self.simhash(tokens)

def __str__(self):

return str(self.hash)

def __long__(self):

return long(self.hash)

def __float__(self):

return float(self.hash)

def simhash(self, tokens):

# Returns a Charikar simhash with appropriate bitlength

v = [0]*self.hashbits

for t in [self._string_hash(x) for x in tokens]:

bitmask = 0

#print (t)

for i in range(self.hashbits):

bitmask = 1 << i

#print(t,bitmask, t & bitmask)

if t & bitmask:

v[i] += 1 #查看当前bit位是否为1，是的话则将该位+1

else:

v[i] += -1 #否则得话，该位减1

fingerprint = 0

for i in range(self.hashbits):

if v[i] >= 0:

fingerprint += 1 << i

#整个文档的fingerprint为最终各个位大于等于0的位的和

return fingerprint

def _string_hash(self, v):

# A variable-length version of Python's builtin hash

if v == "":

return 0

else:

x = ord(v[0])<<7

m = 1000003

mask = 2**self.hashbits-1

for c in v:

x = ((x*m)^ord(c)) & mask

x ^= len(v)

if x == -1:

x = -2

return x

def hamming_distance(self, other_hash):

x = (self.hash ^ other_hash.hash) & ((1 << self.hashbits) - 1)

tot = 0

while x:

tot += 1

x &= x-1

return tot

def similarity(self, other_hash):

a = float(self.hash)

b = float(other_hash)

if a>b: return b/a

return a/b

if __name__ == '__main__':

#看看哪些东西google最看重？标点？

s = '看看哪些东西google最看重？标点？'

hash1 =simhash(s.split())

#print("0x%x" % hash1)

#print ("%s\t0x%x" % (s, hash1))

s = '看看哪些东西google最看重！标点！'

hash2 = simhash(s.split())

#print ("%s\t[simhash = 0x%x]" % (s, hash2))

print '%f%% percent similarity on hash' %(100*(hash1.similarity(hash2)))

print hash1.hamming_distance(hash2),"bits differ out of", hash1.hashbits

VIA

传统的hash函数能够将一样的文本生成一样的hash函数，但是，通过simhash方法，能够差不多相同的文档得到的hash函数也比较相近。

Charikar's hash 通过Charikar‘s has[......]

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python版汉字转拼音脚本【转】

实际上是字典举穷，把汉字码表和拼音对应起来了

#!/usr/bin/env python
# encoding: utf-8
"""
Created by Eric Lo on 2010-05-20.
Copyright (c) 2010 __lxneng@gmail.com__. http://lxneng.com All rights reserved.
"""
class Pinyin():
    def __init__(self, data_path='./Mandarin.dat'):
        self.dict = {}
        for line in open(data_path):
            k, v = line.split('\t')
            self.dict[k] = v
        self.splitter = ''
    def get_pinyin(self, chars=u"你好吗"):
        result = []
        for char in chars:
            key = "%X" % ord(char)
            try:
                result.append(self.dict[key].split(" ")[0].strip()[:-1].lower())
            except:
                result.append(char)
        return self.splitter.join(result)
    def get_initials(self, char=u'你'):
        try:
            return self.dict["%X" % ord(char)].split(" ")[0][0]
        except:
            return char

#!/usr/bin/env python

# encoding: utf-8

"""

Created by Eric Lo on 2010-05-20.

"""

class Pinyin():

def __init__(self, data_path='./Mandarin.dat'):

self.dict = {}

for line in open(data_path):

k, v = line.split('\t')

self.dict[k] = v

self.splitter = ''

def get_pinyin(self, chars=u"你好吗"):

result = []

for char in chars:

key = "%X" % ord(char)

try:

result.append(self.dict[key].split(" ")[0].strip()[:-1].lower())

except:

result.append(char)

return self.splitter.join(result)

def get_initials(self, char=u'你'):

try:

return self.dict["%X" % ord(char)].split(" ")[0][0]

except:

return char

from xpinyin import Pinyin
p = Pinyin()
p.get_pinyin(u"上海")
#输出: 'shanghai'
p.get_initials(u"上")
#输出 'S'

from xpinyin import Pinyin

p = Pinyin()

p.get_pinyin(u"上海")

#输出: 'shanghai'

p.get_initials(u"上")

#输出 'S'

下载数据库：http://github.com/lxneng/xpinyin/raw/master/Ma[......]

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配置Windows下Python2.6的MySQL数据库驱动MySQLdb for Python

官方网站 http://sourceforge.net/projects/mysql-python/ 目前只有py2.5的py2.6的有人打包了

网上流传的很广的帖子是这样的，到这里

http://sourceforge.net/forum/forum.php?thread_id=2[......]

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三种shell脚本调用方法(fork, exec, source)

fork ( /directory/script.sh)

fork是最普通的, 就是直接在脚本里面用/directory/script.sh来调用script.sh这个脚本.

运行的时候开一个sub-shell执行调用的脚本，sub-shell执行的时候, parent-shell还在。

[......]

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正则表达式口诀及教程{转}

正则表达式口诀及教程(推荐)
由 Knightby 撰写 http://www.knightby.net/regular-expressions-formula-and-tutorial-recommended.html
转载自 http://bbs.php.cn/thread-20557-1-[......]

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javascript中函数的隐含参数：arguments

Arguments

该对象代表正在执行的函数和调用它的函数的参数。

[function.]arguments[n]
参数function ：选项。当前正在执行的 Function 对象的名字。 n ：选项。要传递给 Function 对象的从0开始的参数值索引。
说明

A[......]

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IF加套套，比较的时候不用转义(from bones)

整数比较

-eq 等于,如:if [ "$a" -eq "$b" ]
-ne 不等于,如:if [ "$a" -ne "$b" ]
-gt 大于,如:if [ "$a" -gt "$b" ]
-ge 大于等于,如:if [ "$a" -ge[......]

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