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Version: Python

Simple table constructors

new_table​

Columns are created using the following methods:

from deephaven import new_table
from deephaven.column import string_col, int_col

result = new_table(
    [
        int_col("Integers", [1, 2, 3]),
        string_col("Strings", ["These", "are", "Strings"]),
    ]
)

Formula columns​

from deephaven import new_table
from deephaven.column import int_col

var = 3


def f(a, b):
    return a + b


source = new_table([int_col("A", [1, 2, 3, 4, 5]), int_col("B", [10, 20, 30, 40, 50])])

result = source.update(formulas=["X = A + 3 * sqrt(B) + var + (int)f(A, B)"])

Array columns​

from deephaven.column import InputColumn
from deephaven import new_table
from deephaven import dtypes
import numpy as np

int_array = dtypes.array(dtypes.int32, np.array([1, 2, 3], dtype=np.int32))
int_array_col = InputColumn("IntArrayCol", dtypes.int32_array, input_data=[int_array])

source = new_table([int_array_col])

String columns​

from deephaven import new_table
from deephaven.column import string_col, int_col

scores = new_table(
    [
        string_col("Name", ["James", "Lauren", "Zoey"]),
        int_col("Math", [95, 72, 100]),
        int_col("Science", [100, 78, 98]),
        int_col("Art", [90, 92, 96]),
    ]
)

total = scores.update(formulas=["Total = Math + Science + Art"])
average = scores.update(formulas=["Average = (Math + Science + Art) / 3 "])

empty_table​

from deephaven import empty_table

result = empty_table(5)

# Empty tables are often followed with a formula
result1 = result.update(formulas=["X = 5"])

time_table​

from deephaven import time_table

result = time_table(period="PT2S")

ring_table​

from deephaven import time_table, ring_table

source = time_table("PT00:00:01")
result = ring_table(parent=source, capacity=3)

img

input_table​

from deephaven import empty_table, input_table
from deephaven import dtypes as dht

# from an existing table
source = empty_table(10).update(["X = i"])

result = input_table(init_table=source)

# from scratch
my_col_defs = {"Integers": dht.int32, "Doubles": dht.double, "Strings": dht.string}

result2 = input_table(col_defs=my_col_defs)