How to add XML tags new file using an existing text file in python?

Question

So the problem I have is that I need to be able to take an existing text file and make a new file adding xml tags to each line. For example:

Hello
World
This
Is
The
Text

should be written to a new text file like this

<tag1>Hello</tag1>
<tag2>World</tag2>
<tag3>This</tag3>
<tag4>Is</tag4>
<tag5>The</tag5>
<tag6>Text</tag6>

I know how to open and write to a new file but having trouble manipulating the data, I'm still a noob and this is my first question on stackoverflow so any help would be greatly appreciated.

loopbackbee · Accepted Answer · 2012-11-29 05:54:07Z

This is a very simple problem that you should be able to solve on your own. Since you're having some trouble, I'll show you how to, generally, attack most programming problems.

First, divide the problem. You have a text file which you must modify to include xml tags. You've correctly identified that opening and writing to files are separate problems - and you already know how to solve those. Futhermore, it's obvious but worth mentioning that you're dealing with a similar repeating pattern on each line. So, if you know how to transform each line of the text into what you want, you'll have solved the problem. Now, let's look at that first line:

Hello

becomes

<tag1>Hello</tag1>

What steps must be performed in order to transform one into the other? Well, the second is just the first with some text inserted at the beggining and end of the string! This is called string concatenation, and simply googling will find you an answer immediately. Further, you have the issue of the tag number, which is different on each line. This is solved by keeping a counter variable, converting the number to a string, and concatenating it too.

Here's an example of a counter:

for i in range(10):
    print i

and another:

i=0
while i<10:
    print i
    i+=1

That's it. I'm confident that you can solve the problem on your own now.

mattn · Accepted Answer · 2012-11-29 05:58:52Z

1

If you want way to do simply, open the text file with vim and type following.

:%s!\(.*\)!\=printf("<tag%d>%s</tag%d>", line("."), submatch(1), line("."))!g

Or if you want to use python,

from xml.sax.saxutils import escape
with open('file.txt', 'r') as f:
  print "\n".join((lambda y: ["<tag%d>%s</tag%d>" % (i+1, escape(y[i].strip()), i+1) for i in range(0, len(y))])(f.readlines()))

Also an answer from @goncalopp

from xml.sax.saxutils import escape
for i,line in enumerate(open('file.txt')):
  print "<tag{0}>{1}</tag{0}>".format(i+1,escape(line.strip()))

edited Nov 29, 2012 at 5:58

answered Nov 29, 2012 at 5:31

mattn

7,77333 silver badges54 bronze badges

3 Comments

loopbackbee Over a year ago

That looks over complicated. There's no need to import and learn a whole library for something this simple

mattn Over a year ago

@goncalopp used for escape().

loopbackbee Over a year ago

Yes, I noticed. Nothing the OP has posted suggests the need for escaping, IMHO. If he needs escaping later, he'll learn about it, instead of avoiding the problem. It's not just the library, though; compare the readability of your solution to this: for i,line in enumerate(open('file.txt')): print "<tag{0}>{1}</tag{0}>".format(i,line) . Lambdas and list comprehensions have their place, but won't help a self-entitled noob

Avinash Y · Accepted Answer · 2012-11-29 05:28:56Z

-1

>>> f = open('file.txt', 'r')
>>> lines = f.readlines()
>>> for index in range(len(lines)):
...     print '<tag%s>%s</tag%s>'%(index+1, lines[index].strip(), index+1)
... 
<tag1>Hello</tag1>
<tag2>World</tag2>
<tag3>This</tag3>
<tag4>Is</tag4>
<tag5>The</tag5>
<tag6>Text</tag6>
Hope you know how to write into file.

answered Nov 29, 2012 at 5:28

Avinash Y

762 bronze badges

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