Unexpected values

• Most common way column detection fails is a column contains unexpected values so you get a character column.
  • The most common cause is a missing value, recorded using something other than NA.

simple_csv <- "
  x
  10
  .
  20
  30"

read_csv(simple_csv)

## Rows: 4 Columns: 1
## ── Column specification ────────────────────────────────────────────────────────
## Delimiter: ","
## chr (1): x
## 
## ℹ Use `spec()` to retrieve the full column specification for this data.
## ℹ Specify the column types or set `show_col_types = FALSE` to quiet this message.

## # A tibble: 4 × 1
##   x    
##   <chr>
## 1 10   
## 2 .    
## 3 20   
## 4 30