I have a dataframe, "grp_wqdata, that is grouped by the vector "CHEMICAL_NAME":
structure(list(SAMPLE_ID = c("Sampe 1", "Sampe 2", "Sampe 3",
"Sampe 4", "Sampe 5", "Sampe 6", "Sampe 7", "Sampe 8", "Sampe 9",
"Sampe 10", "Sampe 11", "Sampe 12"), CHEMICAL_NAME = c("LEAD",
"LEAD", "LEAD", "LEAD", "LEAD", "LEAD", "LEAD", "LEAD", "LEAD",
"LEAD", "LEAD", "LEAD"), REPORT_RESULT_VALUE = c(0.769, 0.512,
5, 5, 5, 5, 5, 5, 5, 5, 5, 5), REPORT_METHOD_DETECTION_LIMIT = c("0.0100",
"0.0100", "0.500", "0.500", "0.500", "0.500", "0.500", "0.500",
"0.500", "0.500", "0.500", "0.500"), DETECT_FLAG = c("Y", "Y",
"N", "N", "N", "N", "N", "N", "N", "N", "N", "N")), class = c("tbl_df",
"tbl", "data.frame"), row.names = c(NA, -12L))
If the value in vector DETECT_FLAG is "N", then I would like to replace the value that is in REPORT_RESULT_VALUE on that row with the value in REPORT_RESULT_LIMIT in that row.
I have tried the following:
ifelse("N" %in% grp_wqdata$DETECT_FLAG,
replace(grp_wqdata$REPORT_RESULT_VALUE,
grp_wqdata$REPORT_RESULT_VALUE[match(grp_wqdata$DETECT_FLAG == "N")],
grp_wqdata$REPORT_RESULT_LIMIT[match(grp_wqdata$DETECT_FLAG == "N")]),
-999)#end of ifelse
but I continue to get the error
Error in match(grp_wqdata$DETECT_FLAG == "N") : argument "table" is missing, with no default
Does anyone have any suggestions for doing this without a for loop?
grp_wqdata <- structure(list(SAMPLE_ID = c("Sampe 1", "Sampe 2", "Sampe 3",
"Sampe 4", "Sampe 5", "Sampe 6", "Sampe 7", "Sampe 8", "Sampe 9",
"Sampe 10", "Sampe 11", "Sampe 12"), CHEMICAL_NAME = c("LEAD",
"LEAD", "LEAD", "LEAD", "LEAD", "LEAD", "LEAD", "LEAD", "LEAD",
"LEAD", "LEAD", "LEAD"), REPORT_RESULT_VALUE = c(0.769, 0.512,
5, 5, 5, 5, 5, 5, 5, 5, 5, 5), REPORT_METHOD_DETECTION_LIMIT = c("0.0100",
"0.0100", "0.500", "0.500", "0.500", "0.500", "0.500", "0.500",
"0.500", "0.500", "0.500", "0.500"), DETECT_FLAG = c("Y", "Y",
"N", "N", "N", "N", "N", "N", "N", "N", "N", "N")), class = c("tbl_df",
"tbl", "data.frame"), row.names = c(NA, -12L))
grp_wqdata$REPORT_RESULT_VALUE <- ifelse(
grp_wqdata$DETECT_FLAG == 'N',
grp_wqdata$REPORT_METHOD_DETECTION_LIMIT,
grp_wqdata$REPORT_RESULT_VALUE)
SAMPLE_ID CHEMICAL_NAME REPORT_RESULT_VALUE REPORT_METHOD_DETECTION_LIMIT DETECT_FLAG
<chr> <chr> <chr> <chr> <chr>
1 Sampe 1 LEAD 0.769 0.0100 Y
2 Sampe 2 LEAD 0.512 0.0100 Y
3 Sampe 3 LEAD 0.500 0.500 N
4 Sampe 4 LEAD 0.500 0.500 N
5 Sampe 5 LEAD 0.500 0.500 N
6 Sampe 6 LEAD 0.500 0.500 N
7 Sampe 7 LEAD 0.500 0.500 N
8 Sampe 8 LEAD 0.500 0.500 N
9 Sampe 9 LEAD 0.500 0.500 N
10 Sampe 10 LEAD 0.500 0.500 N
11 Sampe 11 LEAD 0.500 0.500 N
12 Sampe 12 LEAD 0.500 0.500 N
Here's how to understand understand what's going on.
If DETECT_FLAG == 'N': Then take the value from REPORT_METHOD_DETECTION_LIMIT.
Otherwise: Take the value from REPORT_RESULT_VALUE
Also, you'll probably want to convert REPORT_VALUE_VALUE and REPORT_METHOD_DETECTION_LIMIT to numeric vectors.
Also, as Jilber pointed out in the comments, we can use with to avoid having to use grp_wqdata$ over and over.
grp_wqdata$REPORT_RESULT_VALUE <- with(grp_wqdata,
ifelse(
DETECT_FLAG == 'N',
REPORT_METHOD_DETECTION_LIMIT,
REPORT_RESULT_VALUE))
When you pass a data.frame as the first argument to with, you can then refer to the columns in your data.frame without having to prefix them with the data.frame name and $ or [[.