如何在R xtable的django html渲染中删除\\ n字符？

Question

I have an xtable generated in R that I want to insert into a template in Django.

The django view is file my_view.py is:

def my_view(request):
    mtcars = open('mtcars.html').readlines()
    context = {'mtcars':mtcars}
    return render(request, 'my_view.html', context)

The xtable rendered in R appears thusly when using readlines() into python:

['<!-- html table generated in R 3.1.2 by xtable 1.7-4 package -->\n',
 '<!-- Sun Jan 18 13:32:17 2015 -->\n',
 '<table border=1>\n',
 '<tr> <th>  </th> <th> mpg </th> <th> cyl </th> <th> disp </th> <th> hp </th> <th> drat </th> <th> wt </th> <th> qsec </th> <th> vs </th> <th> am </th> <th> gear </th> <th> carb </th>  </tr>\n',
 '  <tr> <td align="right"> Mazda RX4 </td> <td align="right"> 21.00 </td> <td align="right"> 6.00 </td> <td align="right"> 160.00 </td> <td align="right"> 110.00 </td> <td align="right"> 3.90 </td> <td align="right"> 2.62 </td> <td align="right"> 16.46 </td> <td align="right"> 0.00 </td> <td align="right"> 1.00 </td> <td align="right"> 4.00 </td> <td align="right"> 4.00 </td> </tr>\n',
 '  <tr> <td align="right"> Mazda RX4 Wag </td> <td align="right"> 21.00 </td> <td align="right"> 6.00 </td> <td align="right"> 160.00 </td> <td align="right"> 110.00 </td> <td align="right"> 3.90 </td> <td align="right"> 2.88 </td> <td align="right"> 17.02 </td> <td align="right"> 0.00 </td> <td align="right"> 1.00 </td> <td align="right"> 4.00 </td> <td align="right"> 4.00 </td> </tr>\n',

The template file my_view.html is:

{% extends 'base.html' %}

{% block content %}
    {{mtcars|safe}}
{% endblock %}

The problem is that the safe rendering takes all the lines in the file and shows \\n characters as shown here:

I've tried working around this by replacing the \\n in Python, but I end up with the empty list rows '' . If I .read() the file the whole thing gets rendered as a comment (the first row has <!-- ).

Is there a way to control the django safe rendering of the html table to remove the \\n or is there a better way to insert the html table?

Note: the html table is generated dynamically, otherwise I'd embed it directly (it is rendered appropriately when I embed the text in the template).

Answer 1

Just use read() instead of readlines() and you should be good. The problem is that you are passing along a list instead of a string and you're not unpacking the list.

So the options are a view like this:

def my_view(request):
    mtcars = open('mtcars.html').read()
    context = {'mtcars': mtcars}
    return render(request, 'my_view.html', context)

Or a template like this:

{% extends 'base.html' %}

{% block content %}
{% for row in mtcars %}
    {{ row|safe }}
{% endfor %}
{% endblock %}

Answer 2

You can remove all the whitespaces from the beginning and ending of a string using the .strip() method:

>>> '   \n\r\n\ntest\n   \r\n   \n'.strip()
'test'

In your case this would be:

def my_view(request):
    mtcars = open('mtcars.html').readlines()
    context = {'mtcars': [mtcar.strip() for mtcar in mtcars]}
    return render(request, 'my_view.html', context)