Search the best match comparing prefixes - python-3.x

I have the numbers codes and text codes like in table1 below. And I have the numbers to search like in table2
for which I want to get the best match for a prefix of minimun length of 3 comparing from left to rigth and show as answer the corresponding TEXT CODE.
If there is an exact match, that would be the answer.
If there is no any value that has at least 3 length prefix then answer would be "not found".
I show some comments explaining the conditions applied in answer expected for each Number to search next to table2.
My current attempt shows the exact matches, but I'm not sure how to compare the values to search for the other conditions, when there is no exact match.
ncode = ["88271","1893","107728","4482","3527","71290","404","5081","7129","33751","3","40489","107724"]
tcode = ["RI","NE","JH","XT","LF","NE","RI","XT","QS","XT","YU","WE","RP"]
tosearch = ["50923","712902","404","10772"]
out = []
out.append([])
out.append([])
for code in tosearch:
for nc in ncode:
if code == nc:
indexOfMatched = ncode.index(nc)
out[0].append(nc)
out[1].append(tcode[indexOfMatched])
>>> out
[['404'], ['RI']]
The expected output would be
out = [
['50923', '712902', '404', '10772'],
['NOT FOUND', 'NE', 'RI', 'JH' ]
]

A simple solution you might consider would be the fuzzy-match library. It compares strings and calculates a similarity score. It really shines with strings rather than numbers, but it could easily be applied to find similar results in your prefix numbers.
Check out fuzzy-match here.
Here is a well written fuzzy-match tutorial.

Related

Python: (partial) matching elements of a list to DataFrame columns, returning entry of a different column

I am a beginner in python and have encountered the following problem: I have a long list of strings (I took 3 now for the example):
ENSEMBL_IDs = ['ENSG00000040608',
'ENSG00000070371',
'ENSG00000070413']
which are partial matches of the data in column 0 of my DataFrame genes_df (first 3 entries shown):
genes_list = (['ENSG00000040608.28', 'RTN4R'],
['ENSG00000070371.91', 'CLTCL1'],
['ENSG00000070413.17', 'DGCR2'])
genes_df = pd.DataFrame(genes_list)
The task I want to perform is conceptually not that difficult: I want to compare each element of ENSEMBL_IDs to genes_df.iloc[:,0] (which are partial matches: each element of ENSEMBL_IDs is contained within column 0 of genes_df, as outlined above). If the element of EMSEMBL_IDs matches the element in genes_df.iloc[:,0] (which it does, apart from the extra numbers after the period ".XX" ), I want to return the "corresponding" value that is stored in the first column of the genes_df Dataframe: the actual gene name, 'RTN4R' as an example.
I want to store these in a list. So, in the end, I would be left with a list like follows:
`genenames = ['RTN4R', 'CLTCL1', 'DGCR2']`
Some info that might be helpful: all of the entries in ENSEMBL_IDs are unique, and all of them are for sure contained in column 0 of genes_df.
I think I am looking for something along the lines of:
`genenames = []
for i in ENSEMBL_IDs:
if i in genes_df.iloc[:,0]:
genenames.append(# corresponding value in genes_df.iloc[:,1])`
I am sorry if the question has been asked before; I kept looking and was not able to find a solution that was applicable to my problem.
Thank you for your help!
Thanks also for the edit, English is not my first language, so the improvements were insightful.
You can get rid of the part after the dot (with str.extract or str.replace) before matching the values with isin:
m = genes_df[0].str.extract('([^.]+)', expand=False).isin(ENSEMBL_IDs)
# or
m = genes_df[0].str.replace('\..*$', '', regex=True).isin(ENSEMBL_IDs)
out = genes_df.loc[m, 1].tolist()
Or use a regex with str.match:
pattern = '|'.join(ENSEMBL_IDs)
m = genes_df[0].str.match(pattern)
out = genes_df.loc[m, 1].tolist()
Output: ['RTN4R', 'CLTCL1', 'DGCR2']

FuzzyWuzzy for very similar records in Python

I have a dataset with which I want to find the closest string match. For that purpose I'm using FuzzyWuzzy in this way
sol=process.extract(t,dev2,scorer=fuzz.token_sort_ratio)
Where t is the string and dev2 is the list to compare to. My problem is that sometimes it has very similar records and options provided by FuzzyWuzzy seems to be lacking. And I've tested with token_sort, token_set, partial_token sort and set, ratio, partial_ratio, and WRatio.
For example, the string Italy - Serie A gives me the following 2 closest matches.
Token_sort_ratio: (92, 'Italy - Serie D');(86, 'Italian - Serie A')
The one wanted is obviously the second one, but character by character is closer the first one, which is a different league.
This happens as well with teams. If, let's say I have a string Buchtholz I would obtains Buchtholz II before I get TSV Buchtholz.
My main guess now would be to try and weight the presence and absence of several characters more heavily, like single capital letters at the end of the string, so if there is a difference in the letter or an absence it is weighted as less close. Or for () and special characters.
I don't know if there is a way to take this into account or you guys have a better approach to get the string that really matches.
Similarity matches often require knowledge of the data being analysed. i.e. it is not just a blind single round of matching. I recommend that you pass your results through more steps of matching, starting with inclusive/optimistic approaches (like token_set_ratio) with low cut off scores and working toward more exclusive/pessimistic approaches with higher cut off scores until you have a clear winner. If you know more about the text you're analyzing, you can even modify the strings as you progress.
In a case I worked on, I did similarity matches of goods movement descriptions. In the descriptions the numbers sequences were more important than the text. e.g. when looking for a match for "SLURRY VALVE 250MM RAGMAX 2000" the 250 and 2000 part of the string are important, otherwise I get a "SLURRY VALVE 50MM RAGMAX 2000" as the best match instead of "VALVE B/F 250MM,RAGMAX 250RAG2000 RAGON" which is a better result.
I put the similarity match process through two steps: 1. Get a bunch of similar matches using an optimistic matching scorer (token_set_ratio) 2. get the number sequences of these results and pass them through another round of matching with a more strict scorer (token_sort_ratio). Doing this gave me the better result in the example I showed above.
Below is some blocks of code that could be of assistance:
here's a function to get numbers from the sequence. (In your case you might use this to exclude numbers from your string instead?)
def get_numbers_from_string(description):
numbers = ''.join((ch if ch in '0123456789.-' else ' ') for ch in description)
numbers = ' '.join([nr for nr in numbers.split()])
return numbers
and here is a portion of the code I used to put the description match through two rounds:
try:
# get close match from goods move that has material numbers
df_material = pd.DataFrame(process.extract(description,
corpus_material,
scorer=fuzz.token_set_ratio),
columns=['Similar Text','Score']
)
if df_material['Score'][df_material['Score']>=cut_off_accuracy_materials].count()>=1:
similar_text = df_material['Similar Text'].iloc[0]
score = df_material['Score'].iloc[0]
if nr_description_numbers>4:
# if there are multiple matches found, then get best number combination match
df_material = df_material[df_material['Score']>=cut_off_accuracy_materials]
new_corpus = list(df_material['Similar Text'])
new_corpus = np.vectorize(get_numbers_from_string)(new_corpus)
df_material['numbers'] = new_corpus
df_numbers = pd.DataFrame(process.extract(description_numbers,
new_corpus,
scorer=fuzz.token_sort_ratio),
columns=['numbers','Score']
)
similar_text = df_material['Similar Text'][df_material['numbers']==df_numbers['numbers'].iloc[0]].iloc[0]
nr_score = df_numbers['Score'].iloc[0]
hope it helps, and good luck

Azure Search Suggester - fuzzy not returning results

I created a new Azure Search Suggester but implemented Fuzzy search with the following code:
ISearchIndexClient indexClient = CreateSearchIndexClient();
var suggestParameters = new SuggestParameters();
suggestParameters.UseFuzzyMatching = true;
suggestParameters.MinimumCoverage = 100;
DocumentSuggestResult response = indexClient.Documents.Suggest(term, "suggester", suggestParameters);
IList<SuggestResult> results = response.Results;
The index contain the string "China", but when I search using the following "chn", no suggestion is return. I expect that fuzzy search will be able to return "China".
Searching for "chi" will return "China" as a suggestion correctly.
Can anyone advise what I am doing wrong? Thank you
The short answer to your question is that we do not expect "chn" to return "china" as a result.
The long answer is: suggestions with fuzzy matching happen in two steps. The first step is attempting to "complete" the last term of the query by finding matching words that have that term as a prefix. Only then do the edit distance kicks in as the second step which is to expand each term in the query using an edit distance of 1.
Since the word "chn" is not a prefix to "china", it won't be returned part of the first step. Since "chn" is 2 edit distance away from "china", its not found in the second step either. On the other side, "chi" is a prefix to "china", so its found during the first step. I expect that if you run the search query with "chna", "china" would be succesfully returned.
Hope this answers your question.

How to extract relationships from a text

I am currently new with NLP and need guidance as of how I can solve this problem.
I am currently doing a filtering technique where I need to brand data in a database as either being correct or incorrect. I am given a structured data set, with columns and rows.
However, the filtering conditions are given to me in a text file.
An example filtering text file could be the following:
Values in the column ID which are bigger than 99
Values in the column Cash which are smaller than 10000
Values in the column EndDate that are smaller than values in StartDate
Values in the column Name that contain numeric characters
Any value that follows those conditions should be branded as bad.
However, I want to extract those conditions and append them to the program that I've made so far.
For instance, for the conditions above, I would like to produce
`if ID>99`
`if Cash<10000`
`if EndDate < StartDate`
`if Name LIKE %[1-9]%`
How can I achieve the above result using the Stanford NLP? (or any other NLP library).
This doesn't look like a machine learning problem; it's a simple parser. You have a simple syntax, from which you can easily extract the salient features:
column name
relationship
target value or target column
The resulting "action rule" is simply removing the "syntactic sugar" words and converting the relationship -- and possibly the target value -- to its symbolic form.
Enumerate all of your critical words for each position in a lexicon. Then use basic string manipulation operators in your chosen implementation language to find the three needed fields.
EXAMPLE
Given the data above, your lexicons might be like this:
column_trigger = "Values in the column"
relation_dict = {
"are bigger than" : ">",
"are smaller than" : "<",
"contain" : "LIKE",
...
}
value_desc = {
"numeric characters" : "%[1-9]%",
...
}
From here, use these items in standard parsing. If you're not familiar with that, please look up the basics of a simple sentence grammar in your favourite programming language, with rules such as such as
SENTENCE => SUBJ VERB OBJ
Does that get you going?

Searching for Number of Term Appearances in Mathematica

I'm trying to search across a large array of textual files in Mathematica 8 (12k+). So far, I've been able to plot the sheer numbers of times that a word appears (i.e. the word "love" appears 5,000 times across those 12k files). However, I'm running into difficulty determining the number of files in which "love" appears once - which might only be in 1,000 files, with it repeating several times in others.
I'm finding the documentation WRT FindList, streams, RecordSeparators, etc. a bit murky. Is there a way to set it up so it finds an incidence of a term once in a file and then moves onto the next?
Example of filelist:
{"89001.txt", "89002.txt", "89003.txt", "89004.txt", "89005.txt", "89006.txt", "89007.txt", "89008.txt", "89009.txt", "89010.txt", "89011.txt", "89012.txt", "89013.txt", "89014.txt", "89015.txt", "89016.txt", "89017.txt", "89018.txt", "89019.txt", "89020.txt", "89021.txt", "89022.txt", "89023.txt", "89024.txt"}
The following returns all of the lines with love across every file. Is there a way to return only the first incidence of love in each file before moving onto the next one?
FindList[filelist, "love"]
Thanks so much. This is my first post and I'm largely learning Mathematica through peer/supervisory help, online tutorials, and the documentation.
In addition to Daniel's answer, you also seem to be asking for a list of files where the word only occurs once. To do that, I'd continue to run FindList across all the files
res =FindList[filelist, "love"]
Then, reduce the results to single lines only, via
lines = Select[ res, Length[#]==1& ]
But, this doesn't eliminate the cases where there is more than one occurrence in a single line. To do that, you could use StringCount and only accept instances where it is 1, as follows
Select[ lines, StringCount[ #, RegularExpression[ "\\blove\\b" ] ] == 1& ]
The RegularExpression specifies that "love" must be a distinct word using the word boundary marker (\\b), so that words like "lovely" won't be included.
Edit: It appears that FindList when passed a list of files returns a flattened list, so you can't determine which item goes with which file. For instance, if you have 3 files, and they contain the word "love", 0, 1, and 2 times, respectively, you'd get a list that looked like
{, love, love, love }
which is clearly not useful. To overcome this, you'll have to process each file individually, and that is best done via Map (/#), as follows
res = FindList[#, "love"]& /# filelist
and the rest of the above code works as expected.
But, if you want to associate the results with a file name, you have to change it a little.
res = {#, FindList[#, "love"]}& /# filelist
lines = Select[res,
Length[ #[[2]] ] ==1 && (* <-- Note the use of [[2]] *)
StringCount[ #[[2]], RegularExpression[ "\\blove\\b" ] ] == 1&
]
which returns a list of the form
{ {filename, { "string with love in it" },
{filename, { "string with love in it" }, ...}
To extract the file names, you simply type lines[[All, 1]].
Note, in order to Select on the properties you wanted, I used Part ([[ ]]) to specify the second element in each datum, and the same goes for extracting the file names.
Help > Documentation Center > FindList item 4:
"FindList[files,text,n]
includes only the first n lines found."
So you could set n to 1.
Daniel Lichtblau

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