Ukuchaza iyunithi yezinhlamvu kanye nokusesha uchungechunge oluncane ngaphakathi kwalo kuyinqubo evamile ekuhlaziyeni umbhalo. Kungaba semayini yedatha, ukubuyisa ulwazi, noma ukukhohlisa kweyunithi yezinhlamvu, sihlala sizithola sihlola ukuthi ingabe iyunithi yezinhlamvu encane, noma iyunithi yezinhlamvu engaphansi, itholakala phakathi kweyunithi yezinhlamvu enkulu. Lona umsebenzi owenziwe ngaphakathi R izinhlelo, ingafezwa ngokushesha nangempumelelo.
U-R uwulimi olwenzelwe izazi zezibalo, futhi luguquguquka kakhulu ekuphatheni isethi ehlukahlukene yezinhlobo zedatha, okuhlanganisa amayunithi ezinhlamvu. Manje, ake sicwilise ekutheni singathola kanjani ngempumelelo nangokushesha ochungechunge abancane phakathi kweyunithi yezinhlamvu ku-R.
Ithola i-Substring ku-R
Singathola uchungechunge oluncane ku-R sisebenzisa umsebenzi grepl(). Lo msebenzi, omfishane kokuthi Ukufanisa Iphethini Yokuchazwa Okujwayelekile Okujwayelekile, kuyingxenye yelabhulali eyisisekelo ye-R, okwenza itholakale kalula kunoma ubani osebenzisa i-R.
Isakhiwo somsebenzi silula, sine-syntax elandelayo:
grepl(pattern, x, ignore.case = FALSE, perl = FALSE, fixed = FALSE, useBytes = FALSE)
Lapha, ipharamitha 'yephethini' iwuchungechunge oluncane esilufunayo futhi u-'x' uwuchungechunge olukhulu esifuna kulo iphethini. Amanye amapharamitha alawula izici ezihlukene zokufanisa, njengokuzwela kwekesi kanye nohlobo lokumataniswa kwephethini.
Ukwephula Ikhodi
Into yokuqala esinayo i-substring esiyifunayo; ake sithi โikatiโ. Intambo eyinhloko lapho sifuna khona lokhu kungase kube โImpungushe ensundu esheshayo igxuma phezu kwenja evilaphayo.โ. Ukusebenzisa umsebenzi we-grepl() kuzobukeka kanje:
main_string <- "Impungushe ensundu esheshayo igxuma phezu kwenja evilaphayo." substring <- "cat" grepl(substring, main_string) [/code] Lokhu kuzonikeza inani le-boolean: IQINISO uma "ikati" litholakala ngaphakathi kokuthi "Impungushe ensundu esheshayo igxuma phezu kwenja evilaphayo.", kanye nokuthi FALSE ngenye indlela.
Ukuzwela kwekesi nge-grepl()
Kubalulekile ukuqaphela ukuthi i-grepl() iyazwela ngokuzenzakalela. Lokhu kulawulwa ipharamitha ethi 'ignore.case', eshintsha ngokuzenzakalelayo ithi FALSE. Uma ufuna ukusesha kungabi nandaba, misa i-ignore.case ibe TRUE.
main_string <- "Impungushe ensundu esheshayo yeqa IKATI elivilaphayo." substring <- "cat" grepl(substring, main_string, ignore.case = TRUE) [/code] Lapha, umsebenzi uzobuyisela TRUE ngoba uzoziba icala uma lifaniswa.
I-Grepl() kanye ne-Vectorization
Enye yezinzuzo eziyinhloko ze-grepl() ukuhambisana kwayo ne-vectorization. Uma u-'x' eyivektha, i-grepl() izosebenzisa umsebenzi kuyo yonke into yevekhtha, ibuyisele ivekhtha enengqondo njengomphumela.
Lawa mathuluzi avumela onjiniyela ukuthi bakhe izinhlelo zokusebenza zombhalo eziqine kakhulu nezisebenza ngempumelelo, kungaba okokuhlola idatha, ukubuyisa ulwazi noma yimuphi umsebenzi ohilela ukukhohlisa kweyunithi yezinhlamvu. R inikeza amandla nokuvumelana nezimo ukwenza le misebenzi kalula.