Thanks. That's a pretty clear example. "Compute the average grade for each socioeconomic group" is obviously useful and it is not expressed naturally with regular arrays.
Cheers, Daniel. On 25 October 2014 18:51, Cedric St-Jean <[email protected]> wrote: > Yeah, whenever you have a matrix of data and each column represents > something different, then using a DataFrame is very convenient (and that's > really all there is to it - convenience). For instance, given student exam > data I might express "Compute the average grade for each socioeconomic > group", where "grade" and "socioeconomic group" are both columns in my > dataframe, and there is one row per student. The same can be done with a > matrix, but it'll be a) longer to write and b) much more error-prone, since > I'll have to write data[1] instead of data[:grade], for instance. > > On Saturday, October 25, 2014 11:44:15 AM UTC-4, John Myles White wrote: >> >> Consider doing research in any domain (e.g. epidemiology, economics, >> psychology, sociology, consumer research,...) where you measure N variables >> (each having a different type) about a single unit of observation. Then the >> DataFrame is the most natural representation of that domain’s data. >> >> — John >> >> On Oct 25, 2014, at 8:40 AM, Daniel Carrera <[email protected]> wrote: >> >> >> There was a time when my job was to write database-driven web >> applications. I worked with MySQL a lot. I understand that a data frame has >> the same type of content as a database, but they do not seem to be used to >> solve the same types of problems as something like MySQL. I thought data >> frames were used in more science-related contexts. >> >> Cheers, >> Daniel. >> >> >> On 25 October 2014 17:27, John Myles White <[email protected]> wrote: >> >>> Have you ever used a database? A DataFrame is just a database that’s >>> stored in memory. >>> >>> — John >>> >>> On Oct 25, 2014, at 5:37 AM, Daniel Carrera <[email protected]> wrote: >>> >>> > Hello, >>> > >>> > This is a fairly naive question. I have observed for the last two >>> years that many people really like data frames. R users obviously like >>> them, and the Python and Julia communities thought it was worth adding that >>> feature to their languages too. However, as an astronomer, I have not yet >>> had a problem that would be solved by data frames. I use Julia to analyze >>> hydrodynamic simulations. I can imagine that data frames could have a role >>> in photographic data where some pixels are missing. >>> > >>> > Are you a scientist or engineer currently using data frames to solve a >>> problem? I would love to hear about what you do with data frames and why >>> you find them useful. >>> > >>> > Cheers, >>> > Daniel. >>> >>> >> >> >> -- >> When an engineer says that something can't be done, it's a code phrase >> that means it's not fun to do. >> >> >> -- When an engineer says that something can't be done, it's a code phrase that means it's not fun to do.
