how to extract index value and element value from pandas dataframe

Question

I have a dataframe that contains the following,

                   Reading
Date                        
2020-05-09 14:54:00    13661
2020-05-09 14:55:00    13672
2020-05-09 14:56:00    14251
2020-05-09 14:59:00    15255

I have figured out how to extract the last element:

lastelement=(series["Reading"].iloc[-1])

which gives me "15255"

Note:the first column is the index not a column in the dataframe as such.

so I also want to extract the index value for that same element (which may not be unique int the readings column), i.e. "2020-05-09 14:59:00"

I can anybody help?

thanks

(forgive me if my question is poor, its my first post on stackoverflow! - I can usually work my answers out from all of the other questions/answers presented here)

CHRD · Accepted Answer · 2020-05-22 11:51:02Z

2

You can simply use df.tail():

df.tail(1)

If you only want the index value, you can add:

df.tail(1).index.values

edited May 22, 2020 at 11:51

answered May 22, 2020 at 11:45

CHRD

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Comments

tuhinsharma121 · Accepted Answer · 2020-05-22 12:10:49Z

1

You can try the following code:-

data = [['2020-05-09 14:54:00', 13661],
        ['2020-05-09 14:55:00', 15255],
        ['2020-05-09 14:55:00', 13672],
        ['2020-05-09 14:56:00', 15255],
        ['2020-05-09 14:56:00', 14251],
        ['2020-05-09 14:59:00', 15255]]
df = pd.DataFrame(data, columns=["Date","Reading"])
df.set_index("Date",inplace=True)
last_element=df.Reading[len(df)-1]
last_element_indices = list(df[df["Reading"]==last_element].index.tolist())
print("Last Element :",last_element)
print("Indices :", last_element_indices)

Expected Output:-

Last Element : 15255
Indices : ['2020-05-09 14:55:00', '2020-05-09 14:56:00', '2020-05-09 14:59:00']

Hope this will solve your problem.

answered May 22, 2020 at 12:10

tuhinsharma121

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Comments

halfer · Accepted Answer · 2021-01-25 01:04:16Z

0

Compare the dataframe to the filtered value, squeeze it to get a boolean array, and index the index to get your values :

df.index[df.eq(df.iloc[-1]).squeeze()]

Index(['2020-05-09 14:55:00', '2020-05-09 14:56:00', '2020-05-09 14:59:00'], dtype='object', name='Date')

edited Jan 25, 2021 at 1:04

halfer

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answered May 22, 2020 at 13:35

sammywemmy

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Comments

Kriti Pawar · Accepted Answer · 2020-05-22 12:03:52Z

-1

For reading and index exact value.

Try:

df.tail(1).Reading.values[0]
df.tail(1).Date.values[0]

edited May 22, 2020 at 12:03

answered May 22, 2020 at 11:53

Kriti Pawar

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