return a named list for single security

[Courvoisier13]

Hi, bdh (and the others probably) returns a dataframe when using 1 security and a named list when using more than 1. This is not very consistent and it would be better if it always returned a named list of dataframes with the name = the security even with 1 security. This would help when using bind_rows for example. It would avoid us having to make special cases for 1 security and creating the list manually.

> bdh(securities = "VOD LN Equity", fields = "PX_LAST", start.date = as.Date("2018-11-05"), end.date = as.Date("2018-11-07"))
        date PX_LAST
1 2018-11-05  150.40
2 2018-11-06  146.28
3 2018-11-07  146.36
> bdh(securities = c("VOD LN Equity", "LLOY LN Equity"), fields = "PX_LAST", start.date = as.Date("2018-11-05"), end.date = as.Date("2018-11-07"))
$`VOD LN Equity`
        date PX_LAST
1 2018-11-05  150.40
2 2018-11-06  146.28
3 2018-11-07  146.44

$`LLOY LN Equity`
        date PX_LAST
1 2018-11-05   58.57
2 2018-11-06   57.71
3 2018-11-07   58.40

[armstrtw]

I disagree, but am not opposed to adding an option to do what you want.

My thoughts are if you are requesting one security only, it’s an interactive use case, and is inconvenient to have to access the first element of a one element list.

However, it should be trivial to test an option to always return a list.

[eddelbuettel]

Also, changing interfaces that many years in generally needs a really good reason.

[Courvoisier13]

I understand about the interface change. I am having to modify the package or write a wrapper function around it, which decreases readability (when sharing). Actually, what you'd really want is to return a dataframe with the names of the instrument as a field. Because my issue is really that. An option with the output like the getbars function would be very useful.

[Courvoisier13]

Hi, I actually double checked and this is how it was done in version 3.6.2. In that version, bdh always returns a named list.

Rblpapi version 0.3.6.2 using Blpapi headers 3.8.18.1 and run-time 3.8.18.1. Please respect the Bloomberg licensing agreement and terms of service. opening a new BBG connection...

bdh(securities = "VOD LN Equity", fields = "PX_LAST", start.date = as.Date("2018-11-05"), end.date = as.Date("2018-11-07")) $VOD LN Equity date PX_LAST 1 2018-11-05 150.40 2 2018-11-06 146.28 3 2018-11-07 147.88

bdh(securities = c("VOD LN Equity", "LLOY LN Equity"), fields = "PX_LAST", start.date = as.Date("2018-11-05"), end.date = as.Date("2018-11-07")) $VOD LN Equity date PX_LAST 1 2018-11-05 150.40 2 2018-11-06 146.28 3 2018-11-07 147.88

$LLOY LN Equity date PX_LAST 1 2018-11-05 58.57 2 2018-11-06 57.71 3 2018-11-07 58.25