Question

为我糟糕的编程道歉，因为我是一个可怕的程序员。我参考：How to access next line in a file(.txt) in Python 在问题实例中，next()模块能够读取下一行。但是，一旦代码返回到for循环，它就不会是“下一行”，而是之后的行。

输入：

a /n
b /n
c /n
d /n

输出：

This line contains a, next line contains b.
This line contains c next line contains d.

是否可以实现诸如

之类的结果

This line contains a, next line contains b
This line contains b next line contains c

编辑 - 抱歉忘记输入代码示例代码：

a = open('file.txt','rb')
for i in a:
 b = next(a)
 print "this line contains %s, next line contains %s" %(a,b)
 a.close()

Answer 1

您可以使用文件对象的readlines方法制作文件行的列表。

由于每一行最后都有一个换行符，如果您希望将其打印在一行后面跟一些其他文本，则要删除它。您可以使用strip字符串对象方法来删除字符串的尾随字符。

迭代这些行时，您可以通过1增加索引来访问列表中的下一行。

我发现在创建文件对象时最好使用with open(...) as file_name:语法，因为它会自动为您关闭文件。

with open('file.txt', 'rb') as text_file:
    lines = [line.strip() for line in text_file.readlines()]
    for index, line in enumerate(lines):
        # Check for last line
        try:
            next_line = lines[index + 1]
        except IndexError:
            print("this line contains %s, and is the end of file." % line)
        else:
            print("this line contains %s, next line contains %s" % (line, next_line))

Answer 2

您可以通过将所有行读入字符串列表来解决您的问题。

a = open('file.txt','rb')
text_as_list = a.readlines()
for idx in range(len(text_as_list)-1):
    print "this line contains %s, next line contains %s" %(text_as_list[idx], text_as_list[idx+1])
a.close()

Answer 3

a = open('file.txt','rb')
prev=a.next()
for i in a:
    print "this line contains %s, next line contains %s" %(prev,i)
    prev=i

a.close()

Answer 4

我认为这样做。但是，您应该考虑更改输出的顺序。通常，您希望先输出当前行，然后输出前一行，因为这是读取文件的顺序。因此，解决方案可能会有点混乱。如果你愿意，可以给一个upvote： - ）

a = open('text.txt','rb')

current_line = " "
previous_line = " "

while (previous_line != ""):

    # In the first step, we continue and do nothing to read the next line so
    # we have both lines.
    if current_line == " " and previous_line == " ":

        # Get the first line.
        current_line = a.readline()
        continue

    # Update the lines.
    previous_line = current_line
    current_line = a.readline()

    # No output if the next line does not exist.
    if current_line == "":

        break

    # Output.
    print "This line contains " + previous_line[0] + ", next line contains " + current_line[0]

a.close()

python读取文件next（）

4 个答案: