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Compare two data frames

Source: R/DFtools.R
compare_df.Rd

A custom function for comparing two data frames of indicator data, to see whether they match up, at a specified number of significant figures. Specifically, this is intended to compare two data frames, without regard to row or column ordering. Rows are matched by the required matchcol argument. Hence, it is different from e.g. all.equal() which requires rows to be ordered. In COINr, typically matchcol is the uCode column, for example.

Usage

compare_df(df1, df2, matchcol, sigfigs = 5)

Arguments

df1

A data frame

df2

Another data frame

matchcol

A common column name that is used to match row order. E.g. this might be uCode.

sigfigs

The number of significant figures to use for matching numerical columns

Value

A list with comparison results. List contains:

  • .$Same: overall summary: if TRUE the data frames are the same according to the rules specified, otherwise FALSE.

  • .$Details: details of each column as a data frame. Each row summarises a column of the data frame, saying whether the column is the same as its equivalent, and the number of differences, if any. In case the two data frames have differing numbers of columns and rows, or have differing column names or entries in matchcol, .$Details will simply contain a message to this effect.

  • .$Differences: a list with one entry for every column which contains different entries. Differences are summarised as a data frame with one row for each difference, reporting the value from df1 and its equivalent from df2.

Details

This function compares numerical and non-numerical columns to see if they match. Rows and columns can be in any order. The function performs the following checks:

  • Checks that the two data frames are the same size

  • Checks that column names are the same, and that the matching column has the same entries

  • Checks column by column that the elements are the same, after sorting according to the matching column

It then summarises for each column whether there are any differences, and also what the differences are, if any.

This is intended to cross-check results. For example, if you run something in COINr and want to check indicator results against external calculations.

This function replaces the now-defunct compareDF() from COINr < v1.0.

Examples

# take a sample of indicator data (including the uCode column)
data1 <- ASEM_iData[c(2,12:15)]
# copy the data
data2 <- data1
# make a change: replace one value in data2 by NA
data2[1,2] <- NA
# compare data frames
compare_df(data1, data2, matchcol = "uCode")
#> $Same
#> [1] FALSE
#> 
#> $Details
#>    Column TheSame                          Comment NDifferent
#> 1   uCode    TRUE      Non-numerical and identical          0
#> 2     LPI   FALSE Numerical and different at 5 sf.          1
#> 3 Flights    TRUE Numerical and identical to 5 sf.          0
#> 4    Ship    TRUE Numerical and identical to 5 sf.          0
#> 5    Bord    TRUE Numerical and identical to 5 sf.          0
#> 
#> $Differences
#> $Differences$LPI
#>   uCode      df1 df2
#> 1   AUT 4.097985  NA
#> 
#>