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Compare data frames in R, In this tutorial we are going to describe how to compare data frames in R.
Let’s create a data frame
data1 <- data.frame(x1 = 1:5,
x2 = LETTERS[1:5])
data2 <- data.frame(x1 = 1:5,
x2 = LETTERS[1:5])
data3 <- data.frame(x1 = 3:7,
x2 = LETTERS[1:5])
In the above data frame data1 and data2 are exactly same and data3 is completely different from other data sets.
Let’s install dplyr package for the function all_equal
install.packages("dplyr")
library("dplyr")
Example 1: Compare Equal Data Frames
Case1:-
In the first case, we’ll compare the first two data sets ie) data1 and data2. Based on all_equal function we can check whether the two data frames are equal or not.
all_equal(data1, data2) [1] TRUE
Now you can see the function returned as TRUE, indicates both data sets are equal.
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Case2:-
Now we can try comparedf function from library arsenal.
By default, the data frames are compared by row-by-row. You can change this using the by= or by.x= and by.y= arguments:
summary(compare(df1, df2)) summary(compare(df1, df2, by = "id")) summary(compare(df1, df2, by = "row.names")) library(arsenal) comparedf(data1, data2)
Compare Object
Function Call: comparedf(x = data1, y = data2) Shared: 2 non-by variables and 5 observations. Not shared: 0 variables and 0 observations. Differences found in 0/2 variables compared. 0 variables compared have non-identical attributes. summary(comparedf(data1, data2)) Table: Summary of data.frames version arg ncol nrow -------- ------ ----- ----- x data1 2 5 y data2 2 5 Table: Summary of overall comparison statistic value ------------------------------------------------------------ ------ Number of by-variables 0 Number of non-by variables in common 2 Number of variables compared 2 Number of variables in x but not y 0 Number of variables in y but not x 0 Number of variables compared with some values unequal 0 Number of variables compared with all values equal 2 Number of observations in common 5 Number of observations in x but not y 0 Number of observations in y but not x 0 Number of observations with some compared variables unequal 0 Number of observations with all compared variables equal 5 Number of values unequal 0 Table: Variables not shared ----------------------- No variables not shared ------------------------ Tble: Other variables not compared -------------------------------- No other variables not compared -------------------------------- Table: Observations not shared --------------------------- No observations not shared --------------------------- Table: Differences detected by variable var.x var.y n NAs ------ ------ --- ---- x1 x1 0 0 x2 x2 0 0 Table: Differences detected ------------------------ No differences detected ------------------------ Table: Non-identical attributes ---------------------------- No non-identical attributes ----------------------------
Case3:-
library(diffdf) diffdf(data1, data2) No issues were found!
Example 2: Compare Unequal Data Frames
Case1:-
all_equal(data2, data3) [1] "- Rows in x but not in y: 1, 2, 3, 4, 5\n- Rows in y but not in x: 1, 2, 3, 4, 5\n"
Now its clearly showing as both the data frames are different and the changes.
Case2:-
Now we can try compared function from library arsenal.
library(arsenal) summary(comparedf(data1, data3))
Compare Object
Table: Summary of data.frames
Table: Summary of data.frames version arg ncol nrow -------- ------ ----- ----- x data1 2 5 y data3 2 5 Table: Summary of overall comparison statistic value ------------------------------------------------------------ ------ Number of by-variables 0 Number of non-by variables in common 2 Number of variables compared 2 Number of variables in x but not y 0 Number of variables in y but not x 0 Number of variables compared with some values unequal 1 Number of variables compared with all values equal 1 Number of observations in common 5 Number of observations in x but not y 0 Number of observations in y but not x 0 Number of observations with some compared variables unequal 5 Number of observations with all compared variables equal 0 Number of values unequal 5 Table: Variables not shared No variables not shared Table: Other variables not compared No other variables not compared Table: Observations not shared No observations not shared Table: Differences detected by variable var.x var.y n NAs ------ ------ --- ---- x1 x1 5 0 x2 x2 0 0 Table: Differences detected var.x var.y ..row.names.. values.x values.y row.x row.y ------ ------ -------------- --------- --------- ------ ------ x1 x1 1 1 3 1 1 x1 x1 2 2 4 2 2 x1 x1 3 3 5 3 3 x1 x1 4 4 6 4 4 x1 x1 5 5 7 5 5 Table: Non-identical attributes No non-identical attributes
Case3:-
library(diffdf) diffdf(data1, data3)
Differences found between the objects!
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A summary is given below.
Not all Values Compared Equal All rows are shown in table below ============================= Variable No of Differences x1 5 All rows are shown in table below ======================================== VARIABLE ..ROWNUMBER.. BASE COMPARE x1 1 1 3 x1 2 2 4 x1 3 3 5 x1 4 4 6 x1 5 5 7
Example 3: Compare different dimensional Data Frames
Let’s create a another data frame,
Case1:-
data4 <- data.frame(x1 = 3:9, x2 = LETTERS[1:7]) all_equal(data2, data4)
[1] “Different number of rows”
Indicates data2 and data 4 contains different number of dimensions.
Case2:-
Now will see how the results appearing in compared
summary(comparedf(data1, data4)) Table: Summary of data.frames version arg ncol nrow -------- ------ ----- ----- x data1 2 5 y data4 2 7 Table: Summary of overall comparison statistic value ------------------------------------------------------------ ------ Number of by-variables 0 Number of non-by variables in common 2 Number of variables compared 2 Number of variables in x but not y 0 Number of variables in y but not x 0 Number of variables compared with some values unequal 1 Number of variables compared with all values equal 1 Number of observations in common 5 Number of observations in x but not y 0 Number of observations in y but not x 2 Number of observations with some compared variables unequal 5 Number of observations with all compared variables equal 0 Number of values unequal 5 Table: Variables not shared ------------------------ No variables not shared ------------------------ Table: Other variables not compared -------------------------------- No other variables not compared -------------------------------- Table: Observations not shared version ..row.names.. observation -------- -------------- ------------ y 6 6 y 7 7 Table: Differences detected by variable var.x var.y n NAs ------ ------ --- ---- x1 x1 5 0 x2 x2 0 0 Table: Differences detected var.x var.y ..row.names.. values.x values.y row.x row.y ------ ------ -------------- --------- --------- ------ ------ x1 x1 1 1 3 1 1 x1 x1 2 2 4 2 2 x1 x1 3 3 5 3 3 x1 x1 4 4 6 4 4 x1 x1 5 5 7 5 5 Table: Non-identical attributes ---------------------------- No non-identical attributes ----------------------------
Case3:-
library(diffdf) diffdf(data1, data4)
Differences found between the objects!
A summary is given below. There are rows in COMPARE that are not in BASE !! All rows are shown in table below =============== ..ROWNUMBER.. --------------- 6 7 --------------- Not all Values Compared Equal All rows are shown in table below ============================= Variable No of Differences ----------------------------- x1 5 ----------------------------- All rows are shown in table below ======================================== VARIABLE ..ROWNUMBER.. BASE COMPARE ---------------------------------------- x1 1 1 3 x1 2 2 4 x1 3 3 5 x1 4 4 6 x1 5 5 7 ----------------------------------------
Conclusion,
However, we tried different packages here and found dplyr package is easy to use and provided quick view of the data sets.
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