Initialise numpy array of unknown length

by

Build a Python list and convert that to a Numpy array. That takes amortized O(1) time per append + O(n) for the conversion to array, for a total of O(n).

    a = []
    for x in y:
        a.append(x)
    a = np.array(a)

More Related Contents:

  1. How to print the full NumPy array, without truncation?
  2. What are the differences between numpy arrays and matrices? Which one should I use?
  3. Convert Python sequence to NumPy array, filling missing values
  4. Numpy array assignment with copy
  5. numpy matrix vector multiplication [duplicate]
  6. How to apply a disc shaped mask to a NumPy array?
  7. How to remove specific elements in a numpy array
  8. Repeating each element of a numpy array 5 times
  9. how does multiplication differ for NumPy Matrix vs Array classes?
  10. Ambiguity in Pandas Dataframe / Numpy Array “axis” definition
  11. How to split/partition a dataset into training and test datasets for, e.g., cross validation?
  12. How to create a numpy array of arbitrary length strings?
  13. Using Numpy Vectorize on Functions that Return Vectors
  14. Numpy modify array in place?
  15. Subsetting a 2D numpy array
  16. How to normalize a 2-dimensional numpy array in python less verbose?
  17. What is the difference between ndarray and array in NumPy?
  18. Numpy individual element access slower than for lists
  19. How to turn a video into numpy array?
  20. Can numpy bincount work with 2D arrays?
  21. Python: slicing a multi-dimensional array
  22. Sort invariant for numpy.argsort with multiple dimensions
  23. Numpy isnan() fails on an array of floats (from pandas dataframe apply)
  24. Concatenate range arrays given start, stop numbers in a vectorized way – NumPy
  25. Numpy array dimensions
  26. Numpy – Replace a number with NaN
  27. Numpy select rows based on condition
  28. Python: how to store a numpy multidimensional array in PyTables?
  29. Passing numpy arrays in Cython to a C function that requires dynamically allocated arrays
  30. Convert list of lists with different lengths to a numpy array [duplicate]

Leave a Comment