How to use pandas

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For smooth practice, the command below on the Write waves by shell must be in the Running state.

sh gen_wave.sh | machbase-neo shell import --timeformat=s EXAMPLE

This example shows how to load data into pandas dataframe via machbase-neo HTTP API.

Load CSV

Import pandas and urllib.

from urllib import parse
import pandas as pd

Make query url for "format": "csv" option, then call read_csv. Use timeformat to specify the precision of time data. s, ms, us and ns(default) are available.

query_param = parse.urlencode({
    "q":"select * from example order by time limit 500",
    "format": "csv",
    "timeformat": "s",
})
df = pd.read_csv(f"http://127.0.0.1:5654/db/query?{query_param}")
df

Load Compressed CSV

Read gzip’ed CSV from HTTP API.

from urllib import parse
import pandas as pd
import requests
import io

query_param = parse.urlencode({
    "q":"select * from example order by time desc limit 1000",
    "format": "csv",
    "timeformat": "s",
    "compress": "gzip",
})
response = requests.get(f"http://127.0.0.1:5654/db/query?{query_param}", timeout=30, stream=True)
df = pd.read_csv(io.BytesIO(response.content))
df

Last updated on Sep 27, 2023

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