Marco many thanks for taking the trouble to help solve this problem, I think the way that you propose is novel at least for me that I know little of working with text in Mathematica, thank you very much for your help, on what you've said at the end on the legality of the books, i want to talk that the end is merely educational but the moderators of the community have the last word, greetings

Hi everyone,

if it was English the function DeleteStopwords would be quite handy. But luckily it is easy to make your own stop word function. So, David, has done all the hard work. (I am not contributing much, but had some time to spare...) So, like David, I import the words.

text = Import["~/Desktop/7_5150.pdf", "Plaintext"];

with TextWords, I get a list of the words:

wordlist = TextWords[text]; 

Problem is I don't have stop words, i.e. "useless" or content-free small words. Luckily there are hundreds of websites with lists of them. This commands imports a list of these words from a website I found:

stopwordsspanish = TextWords@Import["https://sites.google.com/site/kevinbouge/stopwords-lists/stopwords_es.txt?attredirects=0&d=1"];

Here is David's tally:

Reverse@SortBy[Tally[Select[ToLowerCase[wordlist], ! StringMatchQ[#, stopwordsspanish] &]], #[[2]] &]

The word cloud looks like this:

WordCloud[Select[ToLowerCase[wordlist], ! StringMatchQ[#, stopwordsspanish] &]]

Here's a BarChart of that:

BarChart[(Reverse@SortBy[Tally[Select[ToLowerCase[wordlist], !StringMatchQ[#, stopwordsspanish] &]], #[[2]] &])[[1 ;; 20, 2]], ChartLabels -> Evaluate[Rotate[#, Pi/2] & /@ (Reverse@SortBy[Tally[Select[ToLowerCase[wordlist], ! StringMatchQ[#,stopwordsspanish] &]], #[[2]] &])[[1 ;; 20, 1]]]]

Looking at this, it appears to be the most inefficient way to program it; i.e. I do all the heavy StringMatching and Tally twice, but luckily the programmers at Wolfram were taking care of making the code fast so that I can be a bit lazy...

Ok, this was a minimal contribution, but I hope it helps with the stop word problem.

Cheers,

Marco

PS: Is it actually legal to post the pdf of that book online?

Hint: There are free online services that convert pdf files to txt files.

Then you might contemplate whether or how you might use the Mathematica functions StringSplit and Tally.

Then you might want to think of a way to easily extract the information you desire from those. Perhaps looking at the information hidden behind Details in the help page for Sort might be interesting.

If I have made no mistake then 'de' appears the most with 4409 times. I understand that is one of the words that you are not looking for.

After all this you might consider whether 'de' and 'De' should be considered the same or not, whether a word followed by a '.' or ',' is being treated the same as that word without the trailing punctuation and if that is resulting in incorrect counting, etc.

But these hints should get you started.