How to apply a mathematical function to a list of objects in R?

-2

So I have a large list of objects (200+) which only contain a numeric value. I want to apply the same mathematical (get the 80% of the value) function for all of them, but it's not working out for me.

Here's a small example.

a = 680



b = 820



c = 1040



list = as.list(ls())



fun = function(x){x*.8}



for (i in list){

  fun(i)

}

And I get an error saying non-numeric argument to binary operator. I get that this might be happening because the software is applying the function to the names in the list and no the numerical values, but for the life of me I can't make it work and haven't been able to find this exact issue online. I know the answer must be so simple but I'm a newbie, really. Any help is appreciated.

Thank you!!

asked Nov 19 '18 at 18:05

D. Rodríguez

2

change your list to list = mget(ls()) instead of as.list use mget then you can be able to do all the other operations

– Onyambu
Nov 19 '18 at 18:25

This is it. I appreciate Jason's and vectorson's answers, but having 200+ elements in my environment I don't want the create the vector by hand. I didn't know the "mget" function. Thank you so much!

– D. Rodríguez
Nov 19 '18 at 18:29

add a comment |

-2

Here's a small example.

a = 680



b = 820



c = 1040



list = as.list(ls())



fun = function(x){x*.8}



for (i in list){

  fun(i)

}

Thank you!!

asked Nov 19 '18 at 18:05

D. Rodríguez

2

change your list to list = mget(ls()) instead of as.list use mget then you can be able to do all the other operations

– Onyambu
Nov 19 '18 at 18:25

This is it. I appreciate Jason's and vectorson's answers, but having 200+ elements in my environment I don't want the create the vector by hand. I didn't know the "mget" function. Thank you so much!

– D. Rodríguez
Nov 19 '18 at 18:29

add a comment |

-2

Here's a small example.

a = 680



b = 820



c = 1040



list = as.list(ls())



fun = function(x){x*.8}



for (i in list){

  fun(i)

}

Thank you!!

asked Nov 19 '18 at 18:05

D. Rodríguez

Here's a small example.

a = 680



b = 820



c = 1040



list = as.list(ls())



fun = function(x){x*.8}



for (i in list){

  fun(i)

}

Thank you!!

r list function

asked Nov 19 '18 at 18:05

D. Rodríguez

asked Nov 19 '18 at 18:05

D. Rodríguez

asked Nov 19 '18 at 18:05

D. Rodríguez

asked Nov 19 '18 at 18:05

D. Rodríguez

asked Nov 19 '18 at 18:05

D. Rodríguez

2

change your list to list = mget(ls()) instead of as.list use mget then you can be able to do all the other operations

– Onyambu
Nov 19 '18 at 18:25

This is it. I appreciate Jason's and vectorson's answers, but having 200+ elements in my environment I don't want the create the vector by hand. I didn't know the "mget" function. Thank you so much!

– D. Rodríguez
Nov 19 '18 at 18:29

add a comment |

2

change your list to list = mget(ls()) instead of as.list use mget then you can be able to do all the other operations

– Onyambu
Nov 19 '18 at 18:25

This is it. I appreciate Jason's and vectorson's answers, but having 200+ elements in my environment I don't want the create the vector by hand. I didn't know the "mget" function. Thank you so much!

– D. Rodríguez
Nov 19 '18 at 18:29

change your list to list = mget(ls()) instead of as.list use mget then you can be able to do all the other operations

– Onyambu
Nov 19 '18 at 18:25

This is it. I appreciate Jason's and vectorson's answers, but having 200+ elements in my environment I don't want the create the vector by hand. I didn't know the "mget" function. Thank you so much!

– D. Rodríguez
Nov 19 '18 at 18:29

add a comment |

3 Answers
3

active

oldest

votes

You are looking for the mget function: This is a multivariate format of get

thus:

a = 680



b = 820



c = 1040



list = mget(ls())## This is the part you need to change



fun = function(x){x*.8}



for (i in list){

  fun(i)

}

answered Nov 19 '18 at 18:33

Onyambu

15.4k1519

This is it! Thank you Onyambu. Can't upvote yet (too new), but this was the solution for me.

– D. Rodríguez
Nov 19 '18 at 18:34

add a comment |

You get an error because ls() only returns the names of the variables you've defined. ("a", "b" and "c")

Having said that, this example could be more easily be done using regular vector and scalar multiplication.

x = c(680, 820, 1040)

x * .8

If for some reason you want you use a list and function anyway I would recommend using lapply, like so:

a = 680

b = 820

c = 1040



list = list(a, b, c)



fun = function(x){ x*.8 }



lapply(list, fun)

answered Nov 19 '18 at 18:19

vectorson

213

add a comment |

Use eapply to apply a function to all variables in an environment. However, I recommend you to first build a list of numeric variables and use lapply(myList, fun) as variables in an environment can easily be manipulated unintentionally. Refer to the code below:

##### Solution 1 using eapply() #####

# Build a new temporary environment to save all numeric variables

tempEnv <- new.env()

tempEnv$a = 680

tempEnv$b = 820

tempEnv$c = 1040



fun = function(x){x*.8}



# apply fun() to all variables in "tempEnv"

eapply(tempEnv, fun)





##### Solution 2 using lapply() (Recommended) #####

# Define all variables in a list

myList <- list(a = 680, 

               b = 820, 

               c = 1040)



# apply fun() to all values in myList

lapply(myList, fun)

edited Nov 19 '18 at 22:13

answered Nov 19 '18 at 18:19

Jason Jisu Park

1266

add a comment |

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3 Answers
3

active

oldest

votes

3 Answers
3

active

oldest

votes

You are looking for the mget function: This is a multivariate format of get

thus:

a = 680



b = 820



c = 1040



list = mget(ls())## This is the part you need to change



fun = function(x){x*.8}



for (i in list){

  fun(i)

}

answered Nov 19 '18 at 18:33

Onyambu

15.4k1519

This is it! Thank you Onyambu. Can't upvote yet (too new), but this was the solution for me.

– D. Rodríguez
Nov 19 '18 at 18:34

add a comment |

You are looking for the mget function: This is a multivariate format of get

thus:

a = 680



b = 820



c = 1040



list = mget(ls())## This is the part you need to change



fun = function(x){x*.8}



for (i in list){

  fun(i)

}

answered Nov 19 '18 at 18:33

Onyambu

15.4k1519

This is it! Thank you Onyambu. Can't upvote yet (too new), but this was the solution for me.

– D. Rodríguez
Nov 19 '18 at 18:34

add a comment |

You are looking for the mget function: This is a multivariate format of get

thus:

a = 680



b = 820



c = 1040



list = mget(ls())## This is the part you need to change



fun = function(x){x*.8}



for (i in list){

  fun(i)

}

answered Nov 19 '18 at 18:33

Onyambu

15.4k1519

You are looking for the mget function: This is a multivariate format of get

thus:

a = 680



b = 820



c = 1040



list = mget(ls())## This is the part you need to change



fun = function(x){x*.8}



for (i in list){

  fun(i)

}

answered Nov 19 '18 at 18:33

Onyambu

15.4k1519

answered Nov 19 '18 at 18:33

Onyambu

15.4k1519

answered Nov 19 '18 at 18:33

Onyambu

15.4k1519

answered Nov 19 '18 at 18:33

Onyambu

15.4k1519

This is it! Thank you Onyambu. Can't upvote yet (too new), but this was the solution for me.

– D. Rodríguez
Nov 19 '18 at 18:34

add a comment |

This is it! Thank you Onyambu. Can't upvote yet (too new), but this was the solution for me.

– D. Rodríguez
Nov 19 '18 at 18:34

This is it! Thank you Onyambu. Can't upvote yet (too new), but this was the solution for me.

– D. Rodríguez
Nov 19 '18 at 18:34

add a comment |

You get an error because ls() only returns the names of the variables you've defined. ("a", "b" and "c")

Having said that, this example could be more easily be done using regular vector and scalar multiplication.

x = c(680, 820, 1040)

x * .8

If for some reason you want you use a list and function anyway I would recommend using lapply, like so:

a = 680

b = 820

c = 1040



list = list(a, b, c)



fun = function(x){ x*.8 }



lapply(list, fun)

answered Nov 19 '18 at 18:19

vectorson

213

add a comment |

You get an error because ls() only returns the names of the variables you've defined. ("a", "b" and "c")

Having said that, this example could be more easily be done using regular vector and scalar multiplication.

x = c(680, 820, 1040)

x * .8

If for some reason you want you use a list and function anyway I would recommend using lapply, like so:

a = 680

b = 820

c = 1040



list = list(a, b, c)



fun = function(x){ x*.8 }



lapply(list, fun)

answered Nov 19 '18 at 18:19

vectorson

213

add a comment |

You get an error because ls() only returns the names of the variables you've defined. ("a", "b" and "c")

Having said that, this example could be more easily be done using regular vector and scalar multiplication.

x = c(680, 820, 1040)

x * .8

If for some reason you want you use a list and function anyway I would recommend using lapply, like so:

a = 680

b = 820

c = 1040



list = list(a, b, c)



fun = function(x){ x*.8 }



lapply(list, fun)

answered Nov 19 '18 at 18:19

vectorson

213

You get an error because ls() only returns the names of the variables you've defined. ("a", "b" and "c")

Having said that, this example could be more easily be done using regular vector and scalar multiplication.

x = c(680, 820, 1040)

x * .8

If for some reason you want you use a list and function anyway I would recommend using lapply, like so:

a = 680

b = 820

c = 1040



list = list(a, b, c)



fun = function(x){ x*.8 }



lapply(list, fun)

answered Nov 19 '18 at 18:19

vectorson

213

answered Nov 19 '18 at 18:19

vectorson

213

answered Nov 19 '18 at 18:19

vectorson

213

answered Nov 19 '18 at 18:19

vectorson

213

add a comment |

##### Solution 1 using eapply() #####

# Build a new temporary environment to save all numeric variables

tempEnv <- new.env()

tempEnv$a = 680

tempEnv$b = 820

tempEnv$c = 1040



fun = function(x){x*.8}



# apply fun() to all variables in "tempEnv"

eapply(tempEnv, fun)





##### Solution 2 using lapply() (Recommended) #####

# Define all variables in a list

myList <- list(a = 680, 

               b = 820, 

               c = 1040)



# apply fun() to all values in myList

lapply(myList, fun)

edited Nov 19 '18 at 22:13

answered Nov 19 '18 at 18:19

Jason Jisu Park

1266

add a comment |

##### Solution 1 using eapply() #####

# Build a new temporary environment to save all numeric variables

tempEnv <- new.env()

tempEnv$a = 680

tempEnv$b = 820

tempEnv$c = 1040



fun = function(x){x*.8}



# apply fun() to all variables in "tempEnv"

eapply(tempEnv, fun)





##### Solution 2 using lapply() (Recommended) #####

# Define all variables in a list

myList <- list(a = 680, 

               b = 820, 

               c = 1040)



# apply fun() to all values in myList

lapply(myList, fun)

edited Nov 19 '18 at 22:13

answered Nov 19 '18 at 18:19

Jason Jisu Park

1266

add a comment |

##### Solution 1 using eapply() #####

# Build a new temporary environment to save all numeric variables

tempEnv <- new.env()

tempEnv$a = 680

tempEnv$b = 820

tempEnv$c = 1040



fun = function(x){x*.8}



# apply fun() to all variables in "tempEnv"

eapply(tempEnv, fun)





##### Solution 2 using lapply() (Recommended) #####

# Define all variables in a list

myList <- list(a = 680, 

               b = 820, 

               c = 1040)



# apply fun() to all values in myList

lapply(myList, fun)

edited Nov 19 '18 at 22:13

answered Nov 19 '18 at 18:19

Jason Jisu Park

1266

##### Solution 1 using eapply() #####

# Build a new temporary environment to save all numeric variables

tempEnv <- new.env()

tempEnv$a = 680

tempEnv$b = 820

tempEnv$c = 1040



fun = function(x){x*.8}



# apply fun() to all variables in "tempEnv"

eapply(tempEnv, fun)





##### Solution 2 using lapply() (Recommended) #####

# Define all variables in a list

myList <- list(a = 680, 

               b = 820, 

               c = 1040)



# apply fun() to all values in myList

lapply(myList, fun)

edited Nov 19 '18 at 22:13

answered Nov 19 '18 at 18:19

Jason Jisu Park

1266

edited Nov 19 '18 at 22:13

answered Nov 19 '18 at 18:19

Jason Jisu Park

1266

answered Nov 19 '18 at 18:19

Jason Jisu Park

1266

answered Nov 19 '18 at 18:19

Jason Jisu Park

1266

add a comment |

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