You’re looking for #flatten: concatenated = array_of_arrays.flatten By default, this will flatten the lists recursively. #flatten accepts an optional argument to limit the recursion depth – the documentation lists examples to illustrate the difference.
I think there is problem with different index values, so where concat cannot align get NaN: aaa = pd.DataFrame([0,1,0,1,0,0], columns=[‘prediction’], index=[4,5,8,7,10,12]) print(aaa) prediction 4 0 5 1 8 0 7 1 10 0 12 0 bbb = pd.DataFrame([0,0,1,0,1,1], columns=[‘groundTruth’]) print(bbb) groundTruth 0 0 1 0 2 1 3 0 4 1 5 1 print (pd.concat([aaa, … Read more
There are several ways. A simple solution is to add parenthesis: strz = (“This is a line” + str1 + “This is line 2” + str2 + “This is line 3″) If you want each “line” on a separate line you can add newline characters: strz = (“This is a line\n” + str1 + “\n” … Read more
Because both a and b have only one axis, as their shape is (3), and the axis parameter specifically refers to the axis of the elements to concatenate. this example should clarify what concatenate is doing with axis. Take two vectors with two axis, with shape (2,3): a = np.array([[1,5,9], [2,6,10]]) b = np.array([[3,7,11], [4,8,12]]) … Read more
Here is a small test suite: #include <iostream> #include <string> #include <chrono> #include <sstream> int main () { typedef std::chrono::high_resolution_clock clock; typedef std::chrono::duration<float, std::milli> mil; std::string l_czTempStr; std::string s1=”Test data1″; auto t0 = clock::now(); #if VER==1 for (int i = 0; i < 100000; ++i) { l_czTempStr = s1 + “Test data2” + “Test data3”; … Read more
Check this: SELECT GROUP_CONCAT(id) FROM table_level WHERE parent_id = 4 GROUP BY parent_id;
Yes, file.path() R> file.path(“usr”, “local”, “lib”) [1] “usr/local/lib” R> There is also the equally useful system.path() for files in a package: R> system.file(“extdata”, “date_time_zonespec.csv”, package=”RcppBDT”) [1] “/usr/local/lib/R/site-library/RcppBDT/extdata/date_time_zonespec.csv” R> which will get the file extdata/date_time_zonespec.csv irrespective of where the package is installed, and the OS which is very handy. Lastly, there is also R> .Platform$file.sep [1] … Read more
answer = True myvar = “the answer is ” + str(answer) Python does not do implicit casting, as implicit casting can mask critical logic errors. Just cast answer to a string itself to get its string representation (“True”), or use string formatting like so: myvar = “the answer is %s” % answer Note that answer … Read more
You can use itertools.chain for this: from itertools import chain concatenated = chain(range(30), range(2000, 5002)) for i in concatenated: … It works for arbitrary iterables. Note that there’s a difference in behavior of range() between Python 2 and 3 that you should know about: in Python 2 range returns a list, and in Python3 an … Read more
You are close, you want to use np.tile, but like this: a = np.array([0,1,2]) np.tile(a,(3,1)) Result: array([[0, 1, 2], [0, 1, 2], [0, 1, 2]]) If you call np.tile(a,3) you will get concatenate behavior like you were seeing array([0, 1, 2, 0, 1, 2, 0, 1, 2]) http://docs.scipy.org/doc/numpy/reference/generated/numpy.tile.html