#coding:gbk
import os,sys,time
def get_ext(fileName):
pos = fileName.rfind(".")
if pos !=-1:
return fileName[pos:].lower()
else:
return None
def str2int(v):
try:v = int(v)
except:v = 0
return v
def mod(x,y):
return float(x)/y
def printf(format,*args):
sys.stdout.write(format%args)
def sprintf(format,*args):
return format%args
def exit_delay(num):
secnod = num
text = r"after (%02d) secnod exit."
length = len(text)-2
back = ""
for i in range(length):
back = back + "\b"
while (secnod):
sys.stdout.write(text%secnod)
sys.stdout.flush()
time.sleep(1)
sys.stdout.write(back)
secnod = secnod -1;
sys.stdout.write(text%secnod)
sys.stdout.write("\r\n")
def unlink(filename):
try:
os.remove(filename)
printf("删除文件(%s)成功 \r\n",filename)
except WindowsError,e:
if e.errno==2:
printf("文件(%s)不存在 \r\n",filename)
def A(n):
c = 1
for i in range(n):
c *= i+1
return c
def C(n,m):
return A(n)/A(n-m)/A(m)