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#!/usr/bin/env python3
"""Small example that shows how to work with extendeable arrays of different
types, strings included."""
import numpy as np
import tables as tb
# Open a new empty HDF5 file
filename = "earray2.h5"
fileh = tb.open_file(filename, mode="w")
# Get the root group
root = fileh.root
# Create an string atom
a = tb.StringAtom(itemsize=1)
# Use it as a type for the enlargeable array
hdfarray = fileh.create_earray(root, "array_c", a, (0,), "Character array")
hdfarray.append(np.array(["a", "b", "c"]))
# The next is legal:
hdfarray.append(np.array(["c", "b", "c", "d"]))
# but these are not:
# hdfarray.append(array([['c', 'b'], ['c', 'd']]))
# hdfarray.append(array([[1,2,3],[3,2,1]], dtype=uint8).reshape(2,1,3))
# Create an atom
a = tb.UInt16Atom()
hdfarray = fileh.create_earray(
root, "array_e", a, (2, 0, 3), "Unsigned short array"
)
# Create an enlargeable array
a = tb.UInt8Atom()
hdfarray = fileh.create_earray(
root,
"array_b",
a,
(2, 0, 3),
"Unsigned byte array",
tb.Filters(complevel=1),
)
# Append an array to this table
hdfarray.append(
np.array([[1, 2, 3], [3, 2, 1]], dtype=np.uint8).reshape(2, 1, 3)
)
hdfarray.append(
np.array(
[[1, 2, 3], [3, 2, 1], [2, 4, 6], [6, 4, 2]], dtype=np.uint8
).reshape(2, 2, 3)
* 2
)
# The next should give a type error:
# hdfarray.append(array([[1,0,1],[0,0,1]], dtype=Bool).reshape(2,1,3))
# Close the file
fileh.close()
# Open the file for reading
fileh = tb.open_file(filename, mode="r")
# Get the root group
root = fileh.root
a = root.array_c.read()
print("Character array -->", repr(a), a.shape)
a = root.array_e.read()
print("Empty array (yes, this is suported) -->", repr(a), a.shape)
a = root.array_b.read(step=2)
print("Int8 array, even rows (step = 2) -->", repr(a), a.shape)
print("Testing iterator:", end=" ")
# for x in root.array_b.iterrows(step=2):
for x in root.array_b:
print("nrow-->", root.array_b.nrow)
print("Element-->", x)
print("Testing getitem:")
for i in range(root.array_b.shape[0]):
print("array_b[" + str(i) + "]", "-->", root.array_b[i])
# The nrows counts the growing dimension, which is different from the
# first index
for i in range(root.array_b.nrows):
print("array_b[:," + str(i) + ",:]", "-->", root.array_b[:, i, :])
print("array_c[1:2]", repr(root.array_c[1:2]))
print("array_c[1:3]", repr(root.array_c[1:3]))
print("array_b[:]", root.array_b[:])
print(repr(root.array_c))
# Close the file
fileh.close()
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