R - Error Duplicate identifiers for rows

Question

I need to reshape a data frame but there is some problem

I have this command:

library(tidyverse)
data1 = data1 %>% gather(Day, value, Day01:Day31) %>% spread(Station, value)

And I get this error:

Error: Duplicate identifiers for rows (130933, 131029), (389113, 389209), (647293, 647389), (905473, 905569), (1163653, 1163749), (1421833, 1421929), (1680013, 1680109), (1938193, 1938289), (2196373, 2196469), (2454553, 2454649), (2712733, 2712829), (2970913, 2971009), (3229093, 3229189), (3487273, 3487369), (3745453, 3745549), (4003633, 4003729), (4261813, 4261909), (4519993, 4520089), (4778173, 4778269), (5036353, 5036449), (5294533, 5294629), (5552713, 5552809), (5810893, 5810989), (6069073, 6069169), (6327253, 6327349), (6585433, 6585529), (6843613, 6843709), (7101793, 7101889), (7359973, 7360069), (7618153, 7618249), (7876333, 7876429), (130934, 131030), (389114, 389210), (647294, 647390), (905474, 905570), (1163654, 1163750), (1421834, 1421930), (1680014, 1680110), (1938194, 1938290), (2196374, 2196470), (2454554, 2454650), (2712734, 2712830), (2970914, 2971010), (3229094, 3229190), (3487274, 3487370), (3745454, 3745550), (4003634, 4003730), (4261814, 4261910), (4519994, 4520090

The strange thing is that I also get this results:

library(dplyr)
test = rownames_to_column(data1, "VALUE")
length(unique(test$VALUE)) ### Result 258180 = Same as number of rows
length(unique(test$VALUE)) == nrow(test) #### Result TRUE

So in the error if you observer, there are errors which do not exist in my data frame

Answer 1

You can try the below code as spread tries to combine the rows that are uniquely identified after gather. rowid_to_column() is a function that converts row ids to columns.

data2 <- data %>%
    gather(Day, value, Day01:Day31) %>%
    tibble::rowid_to_column() %>%
    spread(Station, value)