只下載循環的第一個文件

Question

我已經寫了一個類，它在調用類實例時從ftp站點（ftp://ladsweb.nascom.nasa.gov/allData/5/MOD11A1/）下載一個文件名的部分文件。後來我寫了一個for循環，並在for循環中集成了類實例，以便下載多個日期範圍內的文件。這是一個日期範圍，因爲這些文件是根據它們生成的日期命名的。所以有每日文件。當你運行代碼時，你被要求輸入一系列的日期。範圍內的第一個文件下載成功，但程序停止並打印以下錯誤那麼當：

Traceback (most recent call last): 
     File "ftplib04Simplified.py", line 42, in <module> 
     FtpDownloader("ladsweb.nascom.nasa.gov","/allData/5/MOD11A1/",a).findFile(10,11) 
     File "ftplib04Simplified.py", line 32, in findFile 
     self.ftp.retrbinary('RETR %s' % filename, open(filename,'wb').write) 
     File "/usr/lib/python3.3/ftplib.py", line 424, in retrbinary 
     with self.transfercmd(cmd, rest) as conn: 
     File "/usr/lib/python3.3/ftplib.py", line 386, in transfercmd 
     return self.ntransfercmd(cmd, rest)[0] 
     File "/usr/lib/python3.3/ftplib.py", line 352, in ntransfercmd 
     resp = self.sendcmd(cmd) 
     File "/usr/lib/python3.3/ftplib.py", line 259, in sendcmd 
     return self.getresp() 
     File "/usr/lib/python3.3/ftplib.py", line 233, in getresp 
     raise error_perm(resp) 
    ftplib.error_perm: 550 No such file. 

    shell returned 1 

我知道純一流的設計將讓我羞愧，但這是完整的代碼，我已經寫： PS這是用Python編寫3.如果您運行的代碼，當問及輸入，請輸入一個日期2001年後

import ftplib 
import math 
import datetime as dt 
import time 
class FtpDownloader: 
    """Downloads raster tiles given the date, and tile row and column number""" 
    def __init__(self,site,directory,raw_date,ftp=None): 
     """logs in to ftp""" 
     self.site=site 
     self.directory=directory 
     self.raw_date=raw_date 
     self.ftp=ftplib.FTP(site) 
     self.ftp.login() 
     self.convert_date() 
    def convert_date(self): 
     """converts YYYY-MM-DD format to year and day of the year""" 
     year=self.raw_date.strftime("%Y") 
     day=self.raw_date.strftime("%j") 
     self.go_to_folder(year,day) 
    def go_to_folder(self,year,day): 
     """sets the current FTP directory""" 
     self.ftp.cwd(self.directory+"%s/%s/" % (year,day)) 
    def findFile(self,h,v,fileList=[]): 
     """checks for the file containing the given h and h and downloads it using retrbinary""" 
     hh= "%02d" % h 
     vv= "%02d" % v 
     tilename = "h%sv%s" % (hh,vv) 
     print ("Image tile %s is downloading..." % tilename) 
     self.ftp.retrlines('NLST',fileList.append) 
     for filename in fileList: 
      if tilename in filename: 
       self.ftp.retrbinary('RETR %s' % filename, open(filename,'wb').write) 
       print ("File downloaded") 
       break 
     else: 
      print (filename, "not found") 
     self.ftp.close() 
start=dt.datetime.strptime(input("Enter a start date in YYYY-MM-DD format "),"%Y-%m-%d") 
end=dt.datetime.strptime(input("Enter an end date in YYYY-MM-DD format "),"%Y-%m-%d") 
for i in range((end-start).days + 1): 
    a=(start+dt.timedelta(days=i)).date() 
    FtpDownloader("ladsweb.nascom.nasa.gov","/allData/5/MOD11A1/",a).findFile(10,11) 

Answer 1

這正是你指示電腦做：break跳出下載循環只要你下載的第一個文件：

def findFile(self,h,v,fileList=[]): 
    """checks for the file containing the given h and h and downloads it using retrbinary""" 
    hh= "%02d" % h 
    vv= "%02d" % v 
    tilename = "h%sv%s" % (hh,vv) 
    print ("Image tile %s is downloading..." % tilename) 
    self.ftp.retrlines('NLST',fileList.append) 
    for filename in fileList: 
     if tilename in filename: 
      self.ftp.retrbinary('RETR %s' % filename, open(filename,'wb').write) 
      print ("File downloaded") 
      break 
    else: 
     print (filename, "not found") 
    self.ftp.close() 

只需更換break爲continue以上，它應該工作。 - 更好的是，因爲tehre在for循環中沒有其他語句，所以完全刪除該行。