Pandas Dateframe query between two dates using dictionary value

Question

I have Pandas dateframe which has two column; ID and dates.
Additionally, I have a dictionary with start and end date and I want to extract data from Pandas dataframe which is between dictionary values.

Below is my data.

Dataframe (df)

ID	Dates
1	20010302
2	20091212
3	20020924

Dictioary
date_dictionary = {‘start_date’:’20020101′, ‘end_date’:’20101231′}

If I use,

extracted = df.query('20020101<=Dates<=20101231')

then it works.
But I wonder why the following code gave me an error; UndefinedVariableError: name ‘start_date’ is not defined.

start_date=int(date_dictionary['start_date'])
end_date=int(date_dictionary['end_date'])
extracted = df.query('start_date<=Dates<=end_date')

I imported ‘date_dictionary’ using from date_dictionary import *.

Please someone why it doesn’t work. And is there any method using dictionary’s value inside the query statement?

Asked By: ymmy

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Source

Answer 1

You can refer to variables in the expression by prefixing them with an ‘@’:

extracted = df.query("@start_date<=Dates<=@end_date")

   ID     Dates
1   2  20091212
2   3  20020924

Have a look at the documentation of query

Answered By: sophocles

Pandas Dateframe query between two dates using dictionary value

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