distinct-values

Reading How to use RxJs distinctUntilChanged? and this , it seems that distinctUntilChanged alters the output stream to only provide distinct contiguous values . I take that to mean that if the same value arrives in immediate succession, you are essentially filtering the stream and only getting one occurrence of that repeated value. So if I write this: this.myFormControl.valueChanges .debounceTime(1000) .distinctUntilChanged() .subscribe(newValue => { console.log('debounced: ', newValue); }); I see no difference in output to this: this.myFormControl.valueChanges .debounceTime(1000) .subscribe

I'm running the following MySQL query to find cars that don't have manuals (and have black wheels, etc.) SELECT `cars`.* FROM `cars` INNER JOIN wheels ON cars.id = wheels.car_id LEFT OUTER JOIN manuals ON cars.id = manuals.car_id WHERE (cars.created_at > '2010-09-09' AND wheels.color = 'Black' AND wheels.created_at < '2011-01-05' AND manuals.car_id IS NULL) The results of the query look correct, but it returns the car with id 27 twice. How do I change the query so that all results are unique (no duplicates)? You could try SELECT DISTINCT instead of SELECT cristian add group by cars.id at the

Warning: I'm very new to using python. I'm trying to graph data using error bars but my data has different values for the error above and below the bar, i.e. 2+.75,2-.32. import numpy as np import matplotlib.pyplot as plt # example data x = (1,2,3,4) y = (1,2,3,4) # example variable error bar values yerr = 0.2 plt.figure() plt.errorbar(x, y, yerr,"r^") plt.show() But I want the error bar above the point to be a specific value like .17 and below the point to be a specific point like .3 Does anyone know how to do this? Thanks! Like this: plt.errorbar(x, y, np.array([[0.3]*len(x), [0.17]*len(x)])

How can I list the distinct values in a vector where the values are replicative? I mean, similarly to the following SQL statement: SELECT DISTINCT product_code FROM data Do you mean unique : R> x = c(1,1,2,3,4,4,4) R> x [1] 1 1 2 3 4 4 4 R> unique(x) [1] 1 2 3 4 Try using the duplicated function in combination with the negation operator "!". Example: wdups <- rep(1:5,5) wodups <- wdups[which(!duplicated(wdups))] Hope that helps. You can also use the sqldf package in R. Z <-sqldf('SELECT DISTINCT tablename.columnname FROM tablename ') If the data is actually a factor then you can use the levels

I want to return a cursor only with distinct values of a column. The column 'Groups' has more items but with only 2 values: 1,2,1,1,1,2,2,2,1 String[] FROM = {Groups,_ID}; public Cursor getGroups(){ //...... return db.query(TABLE_NAME,FROM,null,null,null,null,null); } will return a cursor containing {1,2,1,1,1,2,2,2,1} but I would like to contain just {1,2}. You can have an sql query like this, public Cursor usingDistinct(String column_name) { return db.rawQuery("select DISTINCT "+column_name+" from "+TBL_NAME, null); } you can use distinct argument while making query like this: public Cursor

I can think of sorting them and then going over each element one by one but this is nlogn. Is there a linear method to count distinct elements in a list? Update: - distinct vs. unique If you are looking for "unique" values (As in if you see an element "JASON" more than once, than it is no longer unique and should not be counted) You can do that in linear time by using a HashMap ;) (The generalized / language-agnostic idea is Hash table ) Each entry of a HashMap / Hash table is <KEY, VALUE> pair where the keys are unique (but no restrictions on their corresponding value in the pair) Step 1: