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"""
Sniffs a list of CSV files.
"""
import getml.communication as comm
from .connection import Connection
from .helpers import _retrieve_urls
[docs]def sniff_csv(
name,
fnames,
num_lines_sniffed=1000,
quotechar='"',
sep=",",
skip=0,
colnames=None,
conn=None,
):
"""
Sniffs a list of CSV files.
Args:
name (str):
Name of the table in which the data is to be inserted.
fnames (List[str]):
The list of CSV file names to be read.
num_lines_sniffed (int, optional):
Number of lines analyzed by the sniffer.
quotechar (str, optional):
The character used to wrap strings. Default:`"`
sep (str, optional):
The separator used for separating fields. Default:`,`
skip (int, optional):
Number of lines to skip at the beginning of each
file (Default: 0).
colnames(List[str] or None, optional):
The first line of a CSV file
usually contains the column names. When this is not the case, you need to
explicitly pass them.
conn (:class:`~getml.database.Connection`, optional):
The database connection to be used.
If you don't explicitly pass a connection,
the engine will use the default connection.
Returns:
str: Appropriate `CREATE TABLE` statement.
"""
# -------------------------------------------
conn = conn or Connection()
# -------------------------------------------
if not isinstance(fnames, list):
fnames = [fnames]
fnames_ = _retrieve_urls(fnames)
# -------------------------------------------
# Prepare command.
cmd = dict()
cmd["name_"] = name
cmd["type_"] = "Database.sniff_csv"
cmd["fnames_"] = fnames_
cmd["num_lines_sniffed_"] = num_lines_sniffed
cmd["quotechar_"] = quotechar
cmd["sep_"] = sep
cmd["skip_"] = skip
cmd["conn_id_"] = conn.conn_id
if colnames is not None:
cmd["colnames_"] = colnames
# -------------------------------------------
# Send JSON command to engine.
sock = comm.send_and_get_socket(cmd)
# -------------------------------------------
# Make sure that everything went well.
msg = comm.recv_string(sock)
if msg != "Success!":
sock.close()
comm.engine_exception_handler(msg)
# -------------------------------------------
stmt = comm.recv_string(sock)
sock.close()
return stmt