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up vote 0 down vote favorite

let's say we have two functions:

def ftpConnect(): 
    ftp = FTP('server')
    ftp.login()
    ftp.cwd('/path')

def getFileList():
    ftpConnect()
    files = ftp.nlst()
    print(files)

If I call the getFileList() function it won't work because it doesn't know the ftp var.

I know that if I declare the ftp variable inside ftpConnect() function as global it will work, but I was wondering if there is a better / more elegant way of doing it.

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3 Answers 3

up vote 1 down vote accepted

In my opinion, the most elegant solution would be to make a FTP-class, which would have the ftp-variable as a private attribute.

class FTPConnection(object):
    def __init__(self, server):
        self._ftp = FTP(server)

    def connect(self): 
       self._ftp.login()
       self._ftp.cwd('/path')


    def getFileList():
        files = self._ftp.nlst()
        print(files)

ftp = FTPConnection('server')
ftp.connect()
ftp.getFileList()
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Seems like a good idea, but the name of the class is misleading. –  Matthias Jul 10 '13 at 15:02
up vote 4 down vote

Functions can return values. Return values are cool!

Return ftp from ftpConnect():

def ftpConnect(): 
    ftp = FTP('server')
    ftp.login()
    ftp.cwd('/path')
    # return the value of `ftp` to the caller
    return ftp

def getFileList():
    # assign the return value of `ftpConnect` to a new local variable
    ftp = ftpConnect()
    files = ftp.nlst()
    print(ftp.nlst())

You may also want to look in to object-oriented programming techniques; define a class that handles all your FTP-related operations, and store the FTP server connection as an attribute of the instance.

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Your edit made your answer exactly same as mine. –  Ashwini Chaudhary Jul 10 '13 at 14:44
3  
I misread the code at first, then edited it; if we ended up with the same code then that's because we are both awesome. –  Martijn Pieters Jul 10 '13 at 14:45
    
Great minds think alike. –  Matthias Jul 10 '13 at 15:01
up vote 2 down vote

Return ftp from ftpConnect() and assign the return value to a variable named ftp:

def ftpConnect(): 
    ftp = FTP('server')
    ftp.login()
    ftp.cwd('/path')
    return ftp         #return ftp from here

def getFileList():
    ftp = ftpConnect() # assign the returned value from the
                       # function call to a variable
    files = ftp.nlst()
    print(ftp.nlst())
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