Get a row of a date frame for a given time

Given a forecast/observations data frame and a time, isolate the row with the given time.

Usage

get_time_point(df, t)

Arguments

df

A data frame with a time column.

t

A time.

Value

A data frame with one row, where the time equals t. Raises error if there isn't exactly one row which satisfies this.

Examples

# no rows with time==4
try(casteval:::get_time_point(data.frame(time=1:3,val=4:6), 4))
#> Error in casteval:::get_time_point(data.frame(time = 1:3, val = 4:6),  : 
#>   no rows in data frame with given time

# 2 rows with time==2
try(casteval:::get_time_point(data.frame(time=c(1,2,2,3), val=4:7), 2))
#>   time val
#> 1    2   5
#> 2    2   6

# data.frame(time=2, val=5, val_mean=8)
casteval:::get_time_point(data.frame(time=1:3, val=4:6, val_mean=7:9), 2)
#>   time val val_mean
#> 1    2   5        8