Ampliare la mia comment ad una risposta più dettagliata qui: bisogna avvolgere tolower
all'interno di content_transformer
per non rovinare l'oggetto VCorpus
- qualcosa come:
> library(tm)
> data('crude')
> crude[[1]]$content
[1] "Diamond Shamrock Corp said that\neffective today it had cut its contract prices for crude oil by\n1.50 dlrs a barrel.\n The reduction brings its posted price for West Texas\nIntermediate to 16.00 dlrs a barrel, the copany said.\n \"The price reduction today was made in the light of falling\noil product prices and a weak crude oil market,\" a company\nspokeswoman said.\n Diamond is the latest in a line of U.S. oil companies that\nhave cut its contract, or posted, prices over the last two days\nciting weak oil markets.\n Reuter"
> tm_map(crude, content_transformer(tolower))[[1]]$content
[1] "diamond shamrock corp said that\neffective today it had cut its contract prices for crude oil by\n1.50 dlrs a barrel.\n the reduction brings its posted price for west texas\nintermediate to 16.00 dlrs a barrel, the copany said.\n \"the price reduction today was made in the light of falling\noil product prices and a weak crude oil market,\" a company\nspokeswoman said.\n diamond is the latest in a line of u.s. oil companies that\nhave cut its contract, or posted, prices over the last two days\nciting weak oil markets.\n reuter"
Quale pacchetto è 'tm_map' da? Questo sembra dipendere da un pacchetto non di base. Per favore considera di includere la dichiarazione 'library' per completezza. –
@DanielKrizian: 'tm_map()' è dal pacchetto 'tm', e' tolower() 'è da' base' – smci