Question

我是编程和python语言的新手。

我知道如何在python中打开文件，但问题是如何将文件作为函数的参数打开？

示例：

function(parameter)

以下是我编写代码的方法：

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.

并在您的函数中，返回行列表

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

另一个技巧，python文件对象实际上有一个方法来读取文件的行。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就像你的功能一样。你不必再打电话了。

<强>更新以下是编写代码的方法：

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)

希望这有帮助！

Answer 2

Python允许将多个open（）语句放在一个单独的。你可以用逗号分隔它们。那么你的代码就是：

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')

不，你通过在函数结束时显式返回来获得任何东西。你可以使用return提前退出，但最后你已经退出，并且函数将在没有它的情况下退出。（当然，对于返回值的函数，可以使用return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')

或者您甚至可以修改它，这样一种方式也可以将文件对象作为函数争论

Answer 4

这是一种更简单的打开文件的方法，而无需在Python 3.4中定义自己的函数：

var=open("A_blank_text_document_you_created","type_of_file")
var.write("what you want to write")
print (var.read()) #this outputs the file contents
var.close() #closing the file

以下是文件类型：

"r"：只是为了阅读文件
"w"：只是写一个文件
"r+"：一种允许读取和写入文件的特殊类型

有关详细信息，请参阅this cheatsheet。

Answer 5

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)

如何通过python打开文件

5 个答案: