54
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3
answers
2.6K
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What is the difference between flatten and ravel functions in numpy?
import numpy as np y = np.array(((1,2,3),(4,5,6),(7,8,9))) OUTPUT: print(y.flatten()) [1 2 3 4 5 6
60
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9
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1.3K
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Creating a Pandas DataFrame from a Numpy array: How do I specify the index column and column headers?
I have a Numpy array consisting of a list of lists, representing a two-dimensional array with row labels and c
53
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13
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Converting between datetime, Timestamp and datetime64
How do I convert a numpy.datetime64 object to a datetime.datetime (or Timestamp)? In the following code, I cr
65
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6
answers
1.5K
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What is the difference between Numpy's array() and asarray() functions?
What is the difference between Numpy's array() and asarray() functions? When should you use one rather th
52
votes
5
answers
612
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Converting NumPy array into Python List structure?
How do I convert a NumPy array to a Python List (for example [[1,2,3],[4,5,6]] ), and do it reasonably fast?
55
votes
17
answers
3.1K
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How to add an extra column to a NumPy array
Let’s say I have a NumPy array, a: a = np.array([ [1, 2, 3], [2, 3, 4] ]) And I would like
55
votes
15
answers
786
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How do I create an empty array/matrix in NumPy?
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 c
54
votes
7
answers
1.3K
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Difference between numpy.array shape (R, 1) and (R,)
In numpy, some of the operations return in shape (R, 1) but some return (R,). This will make matrix multiplica
53
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14
answers
1.8K
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How to pretty-print a numpy.array without scientific notation and with given precision?
I'm curious, whether there is any way to print formatted numpy.arrays, e.g., in a way similar to this: x
61
votes
11
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1.4K
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What does numpy.random.seed(0) do?
What does np.random.seed do in the below code from a Scikit-Learn tutorial? I'm not very familiar with Nu
62
votes
5
answers
564
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What are the differences between numpy arrays and matrices? Which one should I use?
What are the advantages and disadvantages of each? From what I've seen, either one can work as a replace
53
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10
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2.5K
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Pandas conditional creation of a series/dataframe column
I have a dataframe along the lines of the below: Type Set 1 A Z 2 B Z
64
votes
18
answers
812
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Find nearest value in numpy array
Is there a numpy-thonic way, e.g. function, to find the nearest value in an array? Example: np.find_nearest
69
votes
7
answers
441
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What is the purpose of meshgrid in Python / NumPy?
Can someone explain to me what is the purpose of meshgrid function in Numpy? I know it creates some kind of gr
66
votes
3
answers
414
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Simple Digit Recognition OCR in OpenCV-Python
I am trying to implement a "Digit Recognition OCR" in OpenCV-Python (cv2). It is just for learning purposes. I
65
votes
8
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415
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Numpy array dimensions
I'm currently trying to learn Numpy and Python. Given the following array: import numpy as np a = np.arr
48
votes
15
answers
435
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Sorting arrays in NumPy by column
How can I sort an array in NumPy by the nth column? For example, a = array([[9, 2, 3], [4, 5, 6],
60
votes
10
answers
1.8K
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Pandas read_csv low_memory and dtype options
When calling df = pd.read_csv('somefile.csv') I get: /Users/josh/anaconda/envs/py27/lib/pytho
59
votes
7
answers
2.9K
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pandas create new column based on values from other columns / apply a function of multiple columns, row-wise
I want to apply my custom function (it uses an if-else ladder) to these six columns (ERI_Hispanic, ERI_AmerInd
55
votes
17
answers
1.5K
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How to find all occurrences of an element in a list
index() will give the first occurrence of an item in a list. Is there a neat trick which returns all indices i
