Replacing characters in a string and returning in python

Question

I'm using Pycharm as the software tool to code in python.

These words are in a text format but they are supposed to return different outputs

word = "<p>Santa is fat</p>"
secondword = "Potato & Tomato"
thirdword = "Koala eats http://koala.org/ a lot</p>"

I want to replace each of the following "<" , ">" , "&" to " < " , " > " , " & "

So the output should look like

outputword = "<p>Santa is fat</p>"
outputsecondword = "Fish & Chips"
outputthirdword = ""&lt;p&gt;Koala eats <a href='http://koala.org/'>http://koala.org/</a> a lot&lt;/p&gt;"

Notice that the third word is a URL. I dont want to use the html library. I'm a noob at Python so please provide me with simple solutions. I considered using lists but whenever I replace a character in the list, it doesn't change

Answer 1

Python comes with batteries included :

import html

word = "<p>Santa is fat</p>"
print(html.escape(word))

Output:

<p>Santa is fat</p>

Answer 2

Without using the html library, you can do the replacements like this:

replacewith = {'<':'lt;', '>':'gt;'}
for w in replacewith:
        word = word.replace(w,replacewith[w])

In [407]: word
Out[407]: 'lt;pgt;Santa is fatlt;/pgt;'

Or, in one line:

 word.replace('<','lt;').replace('>','gt;')

Update:

You can move the code into a function and call it like this:

def replace_char(word, replacewith=replacewith):
    for w in replacewith:
            word = word.replace(w,replacewith[w])
    return word

Calling it with word like below will give you:

replace_char("<p>Santa is fat</p>")
Out[457]: 'lt;pgt;Santa is fatlt;/pgt;'

To get the second one to work, update the dictionary:

In [454]: replacewith.update({'Potato':'Fish', 'Tomato':'Chips', '&': '&',})
In [455]: replace_char("Potato & Tomato", replacewith)
Out[455]: 'Fish & Chips'

You can do the same for any new characters that may appear in other new strings in pretty much the same way. Your input thirdword is missing a <p> right at the beginning.

In [461]: replacewith.update({'http://koala.org/':'<a href="http://koala.org/">http://koala.org/</a>'})
In [463]: replace_char("Koala eats http://koala.org/ a lot</p>", replacewith)
Out[463]: 'Koala eats lt;a href="http://koala.org/"gt;http://koala.org/lt;/agt; a lotlt;/pgt;'