Question

I am trying to determine the best way to save an unknown string on a web page that relates to a specific tag, using Python. E.g.

<div class="pictures">
    <img src="http://some.unknownaddress.com/random_image.jpg" alt="" class="image" height="123" width="123">

What I wish to pull out is the images URL address and use it to download the image. The class “pictures” is unique to the page so I gather I can use that as a reference point to grab the URL, but what I’m not sure of is how to write the code to specifically select what even URL is inbetween the ” ” following that “pictures” class.

I am thinking down the line of using re, but have no idea how to concoct a string to make it select that particualar string. Should I be using Beautiful Soup to help?

Any help would be much appreciated.

Thanks,

Dog.

Answer 1

This is messy but would get the job done. Obviously it’d be better to break this down into functions, etc. to make it smoother. Note that I haven’t tested this script specifically, but I have written other scripts in this ilk to do similar things (break down html, add stuff in, and paste it back together, for instance). It’s a bit tedious, and not pretty, but again…it’ll work.

start = 0
end = 0
charCount = -1
imgTagLocation = []
for character in SourceCode:
    charCount += 1
    if character == "<":
       start = charCount
       end = charCount + 4
       testString = SourceCode[start:end]
       if testString == "<img":
           imgTagLocation.append(start)
           endTag = None
           while not endTag:
               if endTag:
                   break
               else:
                  endCount = -1
                  for char in SourceCode[start:]:
                      endCount += 1
                      if char == ">":
                          endTag = start + endCount
                          imgTagLocation.append(endTag)
           imgTag = SourceCode[imgTagLocation[0]:imgTagLocation[1]
           startInImgTag = 0
           testString = "src"
           excerpt = ""
           while testString != excerpt:
               if testString == excerpt:
                   [[continue to break this down until you are searching for the quotation marks within the "src" part of the img tag, and then return the string between those marks]]
               endInImgTag = startInImgTag + 3
               excerpt = imgTag[startInImgTag:endInImgTag]
               startInImgTag += 1