Category: Python Answers

To filter dataframe rows if value in column is in a set list of values with Python Pandas, we can use the isin method.

For instance, we write

rpt[rpt['STK_ID'].isin(stk_list)]

to call isin to get the STK_ID values that are in the stk_list list and return it.

To fix UnicodeDecodeError when reading CSV file in Pandas with Python, we call Pandas read_csv with the engine argument set to 'python'.

For instance, we write

import pandas as pd
df = pd.read_csv('file_name.csv', engine='python')

to call read_csv with the file path and the engine set to 'python' to let Python decode the CSV content into the data frame df.

To delete a column from a Python Pandas DataFrame, we call the drop method.

For instance, we write

df = df.drop('column_name', 1)

to call df.drop to drop the column_name column and 1 means this is the only column we drop.

To convert JSON to a Python Pandas DataFrame, we can use the json.loads and json.normalize method.

For instance, we write

from urllib2 import Request, urlopen
import json

import pandas as pd    

path1 = '52.974049,-81.205203|52.974298,-81.195755'
request=Request('http://maps.googleapis.com/maps/api/elevation/json?locations='+path1+'&sensor=false')
response = urlopen(request)
elevations = response.read()
data = json.loads(elevations)
df = pd.json_normalize(data['results'])

to get some JSON data from request.

Then we call response.read to read the JSON response into JSON.

Next, we call json.loads to load the JSON data into a dictionary.

And then we call Pandas json_normalize to load the values we want into a Pandas dataframe.

To convert between datetime, Timestamp and datetime64 in Python Pandas, we can use the Timestamp function.

For instance, we write

pd.Timestamp(numpy.datetime64('2012-05-01T01:00:00.000000'))

to call Timestamp on a NumPy datetime64 value.

We can use to_datetime to convert a date time string to a Pandas date time value.

For instance, we write

pd.to_datetime('2022-05-01T01:00:00.000000+0100')

to call pd.to_datetime with a date time string to return a Python datetime value from it.