concat

问题 Im having two jagged lists. First one: List<List<string>> firstList = new List<List<string>>(); { dd ff } { dd ff } { dd ff } Second one: List<List<string>> secondList = new List<List<string>>(); { gg hh } { gg uu } { hh uu } Im having a problem with combining both lists into one like this one: { dd ff gg hh } { dd ff gg uu } { dd ff hh uu } Any Concatenation attempt resulted in just adding secondList elements like another firstList rows like this: { dd ff } { dd ff } { dd ff } { gg hh } { gg

问题 I'm concatenating two dataframes, so I want to one dataframe is located to another. But first I did some transformation to initial dataframe: scaler = MinMaxScaler() real_data = pd.DataFrame(scaler.fit_transform(df[real_columns]), columns = real_columns) And then concatenate: categorial_data = pd.get_dummies(df[categor_columns], prefix_sep= '__') train = pd.concat([real_data, categorial_data], axis=1, ignore_index=True) I dont know why, but number of rows increased: print(df.shape, real_data

问题 I would like to take a given row from a DataFrame and prepend or append to the same DataFrame. My code below does just that, but I'm not sure if I'm doing it the right way or if there is an easier, better, faster way? testdf = df.copy() #get row target_row = testdf.ix[[2],:] #del row from df testdf.drop([testdf.index[2]], axis=0, inplace=True) #concat original row to end or start of df newdf = pd.concat([testdf, target_row], axis=0) Thanks 回答1: Rather than concat I would just assign directly

问题 I have three dataframes: timestamp (with timestamps), dataSun (with timestamps of sunrise and sunset), dataData (with different climate data). Dataframe timestamp has datatype "int64" . timestamp.head() timestamp 0 1521681600000 1 1521681900000 2 1521682200000 3 1521682500000 4 1521682800000 Dataframe dataSun has also datatype "int64" . dataSun.head() sunrise sunset 0 1521696105000 1521740761000 1 1521696105000 1521740761000 2 1521696105000 1521740761000 3 1521696105000 1521740761000 4

问题 I am trying to vertically concatenate two Dask DataFrames I have the following Dask DataFrame: d = [ ['A','B','C','D','E','F'], [1, 4, 8, 1, 3, 5], [6, 6, 2, 2, 0, 0], [9, 4, 5, 0, 6, 35], [0, 1, 7, 10, 9, 4], [0, 7, 2, 6, 1, 2] ] df = pd.DataFrame(d[1:], columns=d[0]) ddf = dd.from_pandas(df, npartitions=5) Here is the data as a Pandas DataFrame A B C D E F 0 1 4 8 1 3 5 1 6 6 2 2 0 0 2 9 4 5 0 6 35 3 0 1 7 10 9 4 4 0 7 2 6 1 2 Here is the Dask DataFrame Dask DataFrame Structure: A B C D E F

问题 function whatTheHeck(obj){ var arr = [] for(o in obj){ arr.concat(["what"]) } return arr } whatTheHeck({"one":1, "two": 2}) The concat function completely fails to do anything. But if I put a breakpoint on that line in Firebug and run the line as a watch it works fine. And the for loop iterates twice but in the end arr still equals []. 回答1: Array.concat creates a new array - it does not modify the original so your current code is actually doing nothing. It does not modify arr . So, you need

问题 i have this function that shows an autosuggest in a form: function searchbyId($params) { $input = strtolower($params['input']); $len = strlen($input); $limit = isset($params['limit']) ? (int) $params['limit']:25; $items=array(); $sql='SELECT DISTINCT nIdentidad, CONCAT(primerNombre, ' ', segundoNombre, ' ', primerApellido, ' ', segundoApellido) AS nombre FROM tarjeta_indent WHERE nIdentidad LIKE \''.$input.'%\' ORDER BY nIdentidad LIMIT '.$limit; $resp=db_query($sql); if($resp && db_num_rows(

问题 Low hours on mysql but starting to probe the edges. Stackoverflow a great resource - thanks everyone. Experimenting with Concat I fell over this issue. I know there will be a way but I just can't figure it out. My example: set @strokes_hole_10 = 6; set @x = 10; set @strokes = concat('strokes_hole_',@x); select @strokes; I looking for @strokes to be the variable value 6 rather than the variable value "strokes_hole_10". I find lots of information on using concat, mostly straight forward

问题 Low hours on mysql but starting to probe the edges. Stackoverflow a great resource - thanks everyone. Experimenting with Concat I fell over this issue. I know there will be a way but I just can't figure it out. My example: set @strokes_hole_10 = 6; set @x = 10; set @strokes = concat('strokes_hole_',@x); select @strokes; I looking for @strokes to be the variable value 6 rather than the variable value "strokes_hole_10". I find lots of information on using concat, mostly straight forward

问题 How to Concat two column in a select statement sql server 2005? Here is my statement Select FirstName,secondName from Table ... Now i did try concating secondName with FirstName by using Select FirstName + ' ' + secondName from Table But some values are NULL in secondName column for some records.. My select statement returns NULL instead of FirstName .. I want to have FirstName if secondName is NULL .. 回答1: SELECT FirstName + ISNULL(' ' + SecondName, '') from Table 回答2: If one of your fields