selected rows from the column as per the values in the rows

Question

i have a df as below: where there are 2 columns, student names and marks.

Stud_name   Marks
Jon         25
john        20
ajay        50
ram         27
jay         61
jess        46
troy        23
mike        42
steve       45
glenn       43

i want few name and their marks.

expected output:

Stud_name   Marks
john        20
ajay        50
jess        46
troy        23
ram         27
glenn       43

please help.

i tried:

pd <- filter(df,Stud_name == "john" , "ajay" , "jess")

Error in filter_impl(.df, quo) : 
Evaluation error: operations are possible only for numeric, logical or 
    complex types.

How should the program decide which lines to return, and how does this differ from the output you are currently getting? Also what code are you using currently? — Haem, Sep 21 '18 at 10:09
no logic just need to get the names and the marks as per the names in the columns as expected output. — Robby star, Sep 21 '18 at 10:09
Use `%in%` instead of `==`, i.e. `filter(df, Stud_name %in% c("john" , "ajay" , "jess"))` — markus, Sep 21 '18 at 10:12

s__ · Accepted Answer · 2018-09-21T10:19:34.373

2

You can try this, if you can think to use a base solution:

# your data
dats <- read.table(text='Stud_name   Marks
Jon         25
                   john        20
                   ajay        50
                   ram         27
                   jay         61
                   jess        46
                   troy        23
                   mike        42
                   steve       45
                   glenn       43',sep='', header=T)

# vector with choosen names
names <- c("john","ajay","jess")
dats[which(dats$Stud_name %in% names),]

or (thanks @markus):

dats[(dats$Stud_name %in% names),]
  Stud_name Marks
2      john    20
3      ajay    50
6      jess    46

edited Sep 21 '18 at 10:19

answered Sep 21 '18 at 10:12

s__

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Question is about `dplyr::filter` error, not about "show me alternative". – zx8754 Sep 21 '18 at 10:17
yeah worked without which. thanks s_t – Robby star Sep 21 '18 at 10:17
Oh, I understood that what OP have tried is with `dplyr::filter`, not that is compulsory. I'll edit the answer, thanks. – s__ Sep 21 '18 at 10:19
yes i was using dplyr. thanks. – Robby star Sep 21 '18 at 10:28

selected rows from the column as per the values in the rows

1 Answers1