python os 库

>>>import os
>>>os.getcwd()
>>>os.chdir(’..’)

>>>os.listdir(’/home/sb/bioinfo/seqs’)
>>>os.path.isfile(’/home/sb’)
>>>os.path.isdir(’/home/sb’)
>>>os.remove(’/home/sb/bioinfo/seqs/ms115.ab1’)
>>>os.rename(’/home/sb/seqs/readme.txt’,’/home/sb/Readme’)
>>>os.mkdir(’/home/sb/processed-seqs’)
>>>os.path.join(os.getcwd(),"images")
>>>os.path.exists(os.path.join(os.getcwd(),"images")) #Checksifgiven path exists
>>>os.path.split(’/home/sb/seqs/ms2333.ab1’)    #(’/home/sb/seqs’,’ms2333.ab1’)
>>>os.path.splitext(’/home/sb/seqs/ms2333.ab1’) #(’/home/sb/seqs/ms2333’,’.ab1’)

for x in os.listdir(mypath):
    if os.path.splitext(x)[1] == ’.fas’:
        fh = open(os.path.join(mypath,x),’U’)


>>>import xml.etree.ElementTreeasET
>>>tree=ET.parse("/home/sb/bioinfo/smallUniprot.xml")


>>>import sys
>>>sys.path
>>>sys.path.append("/home/sb/MyPyModules")


#正则表达
>>>import re
>>>mo=re.search("hello","Helloworld,helloPython!")
>>>mo.group() #’hello’ group() returns the string matched by the REGEX
>>>mo.span()  #(13,18) span() returns a tuple containing the(start,end)
              #positions of the match
>>>text.index("hello")

>>>re.findall("[Hh]ello","Helloworld,helloPython,!") # findall
>>>mos=re.finditer("[Hh]ello","Helloworld,helloPython,!")

>>>rgx=re.compile("[Hh]ello")
>>>rgx.findall("Helloworld,helloPython,!")
>>>rgx.search("Helloworld,helloPython,!")
>>>rgx.match("Helloworld,helloPython,!")
>>>rgx.findall("Helloworld,helloPython,!")
#sub(rpl,str[,count=0])
>>>rgx.sub("",seq)
>>>rgx.subn("",seq) #subn(rpl,str[,count=0]): 匹配次数