The Question : 308 people think this question is useful Here is my code to generate a dataframe: then I got the dataframe: When I type the commmand : I got : According to the reference of pandas, axis=1 stands for columns and I expect the result of the command to be So here is
The Question : 324 people think this question is useful How do I convert a numpy.datetime64 object to a datetime.datetime (or Timestamp)? In the following code, I create a datetime, timestamp and datetime64 objects. Note: it’s easy to get the datetime from the Timestamp: But how do we extract the datetime or Timestamp from a
The Question : 315 people think this question is useful Both function return the same list. Then what is the need of two different functions performing same job. The Question Comments : Ravel usually returns a view into the existing array (sometimes it returns a copy). Flatten returns a new array. Possible duplicate of What
The Question : 326 people think this question is useful I have a Numpy array consisting of a list of lists, representing a two-dimensional array with row labels and column names as shown below: I’d like the resulting DataFrame to have Row1 and Row2 as index values, and Col1, Col2 as header values I can
The Question : 329 people think this question is useful How do I convert a NumPy array to a Python List (for example [[1,2,3],[4,5,6]] ), and do it reasonably fast? The Question Comments : The Answer 1 471 people think this answer is useful Use tolist(): Note that this converts the values from whatever numpy
The Question : 330 people think this question is useful Let’s say I have a NumPy array, a: And I would like to add a column of zeros to get an array, b: How can I do this easily in NumPy? The Question Comments : The Answer 1 196 people think this answer is useful
The Question : 332 people think this question is useful What is the difference between Numpy’s array() and asarray() functions? When should you use one rather than the other? They seem to generate identical output for all the inputs I can think of. The Question Comments : The Answer 1 140 people think this answer
The Question : 335 people think this question is useful What does np.random.seed do in the below code from a Scikit-Learn tutorial? I’m not very familiar with NumPy’s random state generator stuff, so I’d really appreciate a layman’s terms explanation of this. The Question Comments : I found this article very helpful in understanding np.random.seed()
The Question : 336 people think this question is useful How to convert real numpy array to int numpy array? Tried using map directly to array but it did not work. The Question Comments : The Answer 1 441 people think this answer is useful Use the astype method. The Answer 2 70 people think
The Question : 348 people think this question is useful Can someone explain to me what is the purpose of meshgrid function in Numpy? I know it creates some kind of grid of coordinates for plotting, but I can’t really see the direct benefit of it. I am studying “Python Machine Learning” from Sebastian Raschka,
The Question : 339 people think this question is useful I can’t figure out how to use an array or matrix in the way that I would normally use a list. I want to create an empty array (or matrix) and then add one column (or row) to it at a time. At the moment
The Question : 340 people think this question is useful In numpy, some of the operations return in shape (R, 1) but some return (R,). This will make matrix multiplication more tedious since explicit reshape is required. For example, given a matrix M, if we want to do numpy.dot(M[:,0], numpy.ones((1, R))) where R is the
