DataStreamPy - Get Latest Date Point constrained by a Date

Question

I wanted to get the latest UK Policy Rate prior to a certain date so I did this

ds.get_data(tickers="UKPRATE.", start="-1M", end="20260528", freq="M")

But you get an error response $$ER: 0628,UKPRATE.  NO ECONOMIC DATA

However if you do this

ds.get_data(tickers="UKPRATE.", start="-1M", end="20260528", freq="M") the response is

2026-04-30 3.75

2026-05-29 Missing Value

At some point the may data point will be populated and my first attempt will stop failing.

I also tried

ds.get_data(tickers="UKPRATE.", start="-0M", end="20260528", freq="M")

where I got an error Invalid Dates. Start date must be earlier than or same as end date.

What I am after is the latest data point for a series bounded by an end-date.

The -2M thing works but you have to write code to sort a df and get teh latest non nan value.

Archi · Answer

Thanks for your help - thats what I thought

BTW I had a type above it was suppose to be -2M in my row row example - copy and paste error.

However if you do this

ds.get_data(tickers="UKPRATE.", start="-2M", end="20260528", freq="M") the response is

2026-04-30 3.75

2026-05-29 Missing Value

Jirapongse · Answer

@Archi

Thank you for reaching out to us.

As far as I know, the Datastream doesn't provide any parameters to get the latest Date Point constrained by an end date. You may need to contact the Datastream support team directly via LSEG Support to confirm this.

However, you can do it through Python code. For example:

date = '2026-02-25'
df = ds.get_data(
    tickers = 'UKPRATE.',
    freq = 'M',    
    end = date, 
    kind = 1)
df.dropna(inplace=True)
df[df.index <= date].tail(1)

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