Question

I am quite new in python.I want to match string in some lines of a file.Let’s say,
I have string:

british    7
German     8
France     90

And I have some lines in a file as like:

<s id="69-7">...Meanwhile is the studio 7 album by British pop band 10cc.</s>
<s id="15-8">...And Then There Were Three... is the ninth studio album by the german band Genesis 8 and was released in 1978.</s>
<s id="1990-2">Magnum Nitro Express is a France centerfire fire rifle cartridge 90.</s>

I want to get output as like:

<s id="69-7">...Meanwhile is the studio <w2>7</w2> album by <w1>British</w1> pop band 10cc.</s>
<s id="15-8">...And Then There Were Three... is the ninth studio album by the <w1>german</w1> band Genesis <w2>8</w2> and was released in 1978.</s>
<s id="1990-2">Magnum Nitro Express is a <w1>France</w1> centerfire fire rifle cartridge <w2>90</w2>.</s>

I tried with the following code:

for i in file:      
    if left in i and right in i:
        line = i.replace(left, '<w1>' + left + '</w1>')
        lineR = line.replace(right, '<w2>' + right + '</w2>')
        text = text + lineR + "\n"
        continue
     return text

But, it also match string from id.eg.

<s id="69-<w2>7</w2>">...Meanwhile is the studio <w2>7</w2> album by <w1>British</w1> pop band 10cc.</s>

So, is there any way to search string as words not as character so that I can escape <s id="69-<w2>7</w2>"> ?

Thanks in advance for any kind of help.

Answer 1

You should use regular expressions to specifically replace only individual words, not word parts.

Something like

import re
left='british'
right='7'
i1 = re.sub('(?i)(\s+)(%s)(\s+)'%left, '\\1<w1>\\2</w1>\\3', i)
i2 = re.sub('(?i)(\s+)(%s)(\s+)'%right, '\\1<w2>\\2</w2>\\3', i1)
print(i2)

which gives us '<s id="69-7">...Meanwhile is the studio <w2>7</w2> album by <w1>British</w1> pop band 10cc.</s>'

And if such approach leads to errors, you can try a more refined code, like

import re

def do(left, right, line):
    parts = [x for x in re.split('(<[^>]+>)', line) if x]
    for idx, l in enumerate(parts):
        lu = l.upper()
        if (not ('<s' in l or 's>' in l) and
            (left.upper() in lu and right.upper() in lu)):
            l = re.sub('(?i)(\s+)(%s)(\s+)'%left, '\\1<w1>\\2</w1>\\3', l)
            l = re.sub('(?i)(\s+)(%s)(\s+)'%right, '\\1<w2>\\2</w2>\\3', l)
            parts[idx] = l

    return ''.join(parts)


line = '<s id="69-7">...Meanwhile is the studio 7 album by British pop band 10cc.</s>'
print(do('british', '7', line))
print(do('british', '-7', line))