PyTable

pytable_example.py

import tables as tb

class Record(tb.IsDescription):
    first_track_id = tb.StringCol(16)  # 16-character String
    second_tracK_id = tb.StringCol(16)  # 16-character String
    distance = tb.Float32Col()  # Float (single-precision)
    
# Open a file in "w"rite mode
fileh = tb.open_file("table1.h5", mode="w")

# Create a new group
group = fileh.create_group(fileh.root, "newgroup")

# Create a new table in newgroup group
table = fileh.create_table(group, 'table', Record, "A table",
                           tb.Filters(1))
single_record = table.row

# Fill the table with 10 particles
for i in range(28000000):
    # First, assign the values to the Particle record
    single_record['first_track_id'] = "track_id_1"
    single_record['second_tracK_id'] = "track_id_2"
    single_record['distance'] = 0.5
    single_record.append()

# We need to flush the buffers in table in order to get an
# accurate number of records on it.
table.flush()
fileh.close()

k = 0
with tb.open_file("table1.h5", mode="r") as h5file:
    table = h5file.root.newgroup.table
    for x in table.iterrows():
        if k < 10:
            print(x['distance'])
        k += 1
print(k)