Crear, agregar y modificar lista en R

En el lenguaje de programación R, la lista es una estructura de datos unidimensional que puede contener múltiples elementos de tipo de datos. En este artículo, vamos a crear una lista y agregar datos a la lista y modificar los elementos de la lista.

Creando una lista

La lista se puede crear usando la función list().

Sintaxis :

lista(valor1,valor2,………….,valorn)

donde los valores son las entradas a la lista.

Ejemplo :

# vector with names
names=c("bobby","pinkey","rohith","gnanu")
 
# vector with marks
marks=c(78,90,100,100)
 
# address vector
address=c("kakumanu","hyd","hyd","hyd")
 
# pass these vectors as inputs to the list
# address vector
student=list(names,marks,address)
print(student)

Producción:

Agregar datos a la lista

Agregar a una lista significa agregar un valor al último de una lista ya existente. Vamos a agregar dos listas usando la función append()

Sintaxis:

agregar (lista1, lista2)

Ejemplo:

# vector with names
names=c("bobby","pinkey","rohith","gnanu")
 
# vector with marks
marks=c(78,90,100,100)
 
# address vector
address=c("kakumanu","hyd","hyd","hyd")
 
# college values
college=c("vignan","vignan","vignan","vignan")
 
# pass these vectors as inputs to the list
student1=list(student1_names=names,student1_marks=marks,
              student1_address=address,student1_college=college)
 
# vector with names
names=c("ravi","devi","siree","priyank")
 
# vector with marks
marks=c(78,90,100,100)
 
# address vector
address=c("hyd","hyd","hyd","hyd")
 
# college values
college=c("vvit","vvit","vvit","vvit")
 
# pass these vectors as inputs to the list
# address vector
student2=list(student2_names=names,student2_marks=marks,
              student2_address=address,student2_college=college)
 
# append list 1 and list 2
print(append(student1,student2))

Producción:

También podemos agregar una sola columna en un marco de datos a otro usando el operador $.

Sintaxis:

agregar (marco de datos 1 $nombre de columna, marco de datos 2 $nombre de columna)

Programa:

# vector with names
names=c("bobby","pinkey","rohith","gnanu")
 
# vector with marks
marks=c(78,90,100,100)
 
# address vector
address=c("kakumanu","hyd","hyd","hyd")
 
# college values
college=c("vignan","vignan","vignan","vignan")
 
# pass these vectors as inputs to the list
student1=list(student1_names=names,student1_marks=marks,
              student1_address=address,student1_college=college)
 
# vector with names
names=c("ravi","devi","siree","priyank")
 
# vector with marks
marks=c(78,90,100,100)
 
# address vector
address=c("hyd","hyd","hyd","hyd")
 
# college values
college=c("vvit","vvit","vvit","vvit")
 
# pass these vectors as inputs to the list
# address vector
student2=list(student2_names=names,student2_marks=marks,
              student2_address=address,student2_college=college)
 
# append list 1 - student marks and list 2 - student marks
print(append(student1$student1_marks,student2$student2_marks))

Producción:

[1]  78  90 100 100  78  90 100 100

Modificar los elementos de la lista

Modificar una lista significa cambiar la representación inicial de la lista que puede incluir operaciones como cambiar o actualizar valores y eliminar. Podemos modificar los elementos de la lista usando el operador de índice.

operador de índice:

 [[]]

Sintaxis :

list_name[[n]]=”nuevo_elemento_nombre

donde n es el valor del índice

Ejemplo:

# vector with names
names=c("bobby","pinkey","rohith","gnanu")
 
# vector with marks
marks=c(78,90,100,100)
 
# address vector
address=c("kakumanu","hyd","hyd","hyd")
 
# college values
college=c("vignan","vignan","vignan","vignan")
 
# pass these vectors as inputs to the list
student1=list(names,marks,address,college)
 
# display 1 st row 2 nd element
print(paste("1 st one - 2 nd element is : ",student1[[1]][2]))
 
# modify pinky to gajji
student1[[1]][2]="gajji"
print(paste("Modified 1 st one - 2 nd element is : ",student1[[1]][2]))

Producción:

[1] "1 st one - 2 nd element is :  pinkey"
[1] "Modified 1 st one - 2 nd element is :  gajji"

También podemos modificar el índice completo a la vez,

Ejemplo:

# vector with names
names=c("bobby","pinkey","rohith","gnanu")
# vector with marks
marks=c(78,90,100,100)
# address vector
address=c("kakumanu","hyd","hyd","hyd")
# college values
college=c("vignan","vignan","vignan","vignan")
# pass these vectors as inputs to the list
student1=list(names,marks,address,college)
 
# display 2 nd index
print(paste("2 nd index elements are : ",student1[[2]]))
# modify the whole content of 2 nd index
student1[[2]]=c(45,56,54,45)
 
print(paste("Modified 2 nd index elements are : ",student1[[2]]))

Producción:

La modificación incluye también la eliminación. Podemos eliminar un elemento particular de la lista asignando un índice de lista con el operador NULL.

Sintaxis :

nombre_lista[[número_índice]]=NULO

Ejemplo:

# vector with names
names=c("bobby","pinkey","rohith","gnanu")
 
# vector with marks
marks=c(78,90,100,100)
 
# address vector
address=c("kakumanu","hyd","hyd","hyd")
 
# college values
college=c("vignan","vignan","vignan","vignan")
 
# pass these vectors as inputs to the list
student1=list(names,marks,address,college)
 
# deleting first item IE names vector
student1[[1]]=NULL
 
# display list
print(student1)

Producción: