Joining sf object with data (2)

inner_join(x, y, by = "a")

## Simple feature collection with 1 feature and 2 fields
## Geometry type: POINT
## Dimension:     XY
## Bounding box:  xmin: 1 ymin: 1 xmax: 1 ymax: 1
## CRS:           NA
##   a letter        geom
## 1 2      k POINT (1 1)