如何通过python打开文件

Question

我对编程和python语言非常陌生。

我知道如何在python中打开文件，但问题是如何打开文件作为函数的参数？

例如：

function(parameter) 

这里是我已经写了代码：

def function(file): 
    with open('file.txt', 'r') as f: 
     contents = f.readlines() 
    lines = [] 
    for line in f: 
     lines.append(line) 
    print(contents)  

Answer 1

您可以轻松地传递文件对象。

with open('file.txt', 'r') as f: #open the file 
    contents = function(f) #put the lines to a variable. 

，并在你的函数，返回行

def function(file): 
    lines = [] 
    for line in f: 
     lines.append(line) 
    return lines 

另一个窍门的列表，Python文件对象实际上有读取文件的行的方法。像这样：

with open('file.txt', 'r') as f: #open the file 
    contents = f.readlines() #put the lines to a variable (list). 

使用第二种方法，readlines就像你的功能。您不必再次调用它。

更新 这里是你应该怎么写代码：

第一种方法：

def function(file): 
    lines = [] 
    for line in f: 
     lines.append(line) 
    return lines 
with open('file.txt', 'r') as f: #open the file 
    contents = function(f) #put the lines to a variable (list). 
    print(contents) 

第二个：

with open('file.txt', 'r') as f: #open the file 
    contents = f.readlines() #put the lines to a variable (list). 
    print(contents) 

希望这有助于！

Answer 2

Python允许把多个打开的（）语句在一个单一的与。你用逗号分开它们。您的代码将是：

def filter(txt, oldfile, newfile): 
    '''\ 
    Read a list of names from a file line by line into an output file. 
    If a line begins with a particular name, insert a string of text 
    after the name before appending the line to the output file. 
    ''' 

    with open(newfile, 'w') as outfile, open(oldfile, 'r', encoding='utf-8') as infile: 
     for line in infile: 
      if line.startswith(txt): 
       line = line[0:len(txt)] + ' - Truly a great person!\n' 
      outfile.write(line) 

# input the name you want to check against 
text = input('Please enter the name of a great person: ')  
letsgo = filter(text,'Spanish', 'Spanish2') 

而且不，你不会在你的函数的末尾加一个明确的返回来获得任何东西。你可以使用return来尽早退出，但最后你会得到它，并且没有它，函数将退出。 （当然，如果函数返回一个值，则使用return来指定要返回的值。）

Answer 3

def fun(file): 
    contents = None 

    with open(file, 'r') as fp: 
     contents = fp.readlines() 

    ## if you want to eliminate all blank lines uncomment the next line 
    #contents = [line for line in ''.join(contents).splitlines() if line] 

    return contents 

print fun('test_file.txt') 

或者你甚至可以修改此，这种方式需要的文件对象作为函数arguement以及

Answer 4

def main(): 
     file=open("chirag.txt","r") 
     for n in file: 
       print (n.strip("t")) 
     file.close() 
if __name__== "__main__": 
     main() 


the other method is 


with open("chirag.txt","r") as f: 
     for n in f: 
       print(n)