CSV Cheat Sheet

# Create a table
from deephaven import empty_table

source = empty_table(100).update(
    formulas=[
        "X = 0.1 * i",
        "SinX = X % 0.2 < 0.01 ? NULL_DOUBLE : sin(X)",
        "CosX = cos(X)",
        "TanX = tan(X)",
    ]
)

# Write to a local file
# `(null)` for null cells
from deephaven import write_csv

write_csv(source, "/data/TrigFunctions.csv")

# Write a subset of data
write_csv(source, "/data/Cosine.csv", ["X", "SinX"])

# Read from a local file
from deephaven import read_csv

result = read_csv("/data/TrigFunctions.csv")

# Read from a csv from URL
iris = read_csv(
    "https://media.githubusercontent.com/media/deephaven/examples/main/Iris/csv/iris.csv"
)

# Read headerless, default column names
deniro_default = read_csv(
    "https://media.githubusercontent.com/media/deephaven/examples/main/DeNiro/csv/deniro_headerless.csv",
    headless=True,
)

# Read headerless, provide names for header
import deephaven.dtypes as dht

header = {"Year": dht.int64, "Score": dht.int64, "Title": dht.string}
deniro_header = read_csv(
    "https://media.githubusercontent.com/media/deephaven/examples/main/DeNiro/csv/deniro_headerless.csv",
    header=header,
    headless=True,
)

# Read files with other delimiters
deniro_tsv = read_csv(
    "https://raw.githubusercontent.com/deephaven/examples/main/DeNiro/csv/deniro.tsv",
    delimiter="\t",
)
deniro_psv = read_csv(
    "https://raw.githubusercontent.com/deephaven/examples/main/DeNiro/csv/deniro.psv",
    delimiter="|",
)