Tables with labels in R

Introduction

expss computes and displays tables with support for 'SPSS'-style labels, multiple / nested banners, weights, multiple-response variables and significance testing. There are facilities for nice output of tables in 'knitr', R notebooks, 'Shiny' and 'Jupyter' notebooks. Proper methods for labelled variables add value labels support to base R functions and to some functions from other packages. Additionally, the package offers useful functions for data processing in marketing research / social surveys - popular data transformation functions from 'SPSS' Statistics and 'Excel' ('RECODE', 'COUNT', 'COUNTIF', 'VLOOKUP', etc.). Package is intended to help people to move data processing from 'Excel'/'SPSS' to R. See examples below. You can get help about any function by typing ?function_name in the R console.

Links

Installation

expss is on CRAN, so for installation you can print in the console install.packages("expss").

Cross-tablulation examples

We will use for demonstartion well-known mtcars dataset. Let's start with adding labels to the dataset. Then we can continue with tables creation.

library(expss)
data(mtcars)
mtcars = apply_labels(mtcars,
                      mpg = "Miles/(US) gallon",
                      cyl = "Number of cylinders",
                      disp = "Displacement (cu.in.)",
                      hp = "Gross horsepower",
                      drat = "Rear axle ratio",
                      wt = "Weight (1000 lbs)",
                      qsec = "1/4 mile time",
                      vs = "Engine",
                      vs = c("V-engine" = 0,
                             "Straight engine" = 1),
                      am = "Transmission",
                      am = c("Automatic" = 0,
                             "Manual"=1),
                      gear = "Number of forward gears",
                      carb = "Number of carburetors"
)

For quick cross-tabulation there are fre and cross family of function. For simplicity we demonstrate here only cross_cpct which calculates column percent. Documentation for other functions, such as cross_cases for counts, cross_rpct for row percent, cross_tpct for table percent and cross_fun for custom summary functions can be seen by typing ?cross_cpct and ?cross_fun in the console.

# 'cross_*' examples
# just simple crosstabulation, similar to base R 'table' function
cross_cases(mtcars, am, vs)

# Table column % with multiple banners
cross_cpct(mtcars, cyl, list(total(), am, vs))

# magrittr pipe usage and nested banners
mtcars %>% 
    cross_cpct(cyl, list(total(), am %nest% vs))      

We have more sophisticated interface for table construction with magrittr piping. Table construction consists of at least of three functions chained with pipe operator: %>%. At first we need to specify variables for which statistics will be computed with tab_cells. Secondary, we calculate statistics with one of the tab_stat_* functions. And last, we finalize table creation with tab_pivot, e. g.: dataset %>% tab_cells(variable) %>% tab_stat_cases() %>% tab_pivot(). After that we can optionally sort table with tab_sort_asc, drop empty rows/columns with drop_rc and transpose with tab_transpose. Resulting table is just a data.frame so we can use usual R operations on it. Detailed documentation for table creation can be seen via ?tables. For significance testing see ?significance. Generally, tables automatically translated to HTML for output in knitr or Jupyter notebooks. However, if we want HTML output in the R notebooks or in the RStudio viewer we need to set options for that: expss_output_rnotebook() or expss_output_viewer().

# simple example
mtcars %>% 
    tab_cells(cyl) %>% 
    tab_cols(total(), am) %>% 
    tab_stat_cpct() %>% 
    tab_pivot()

# table with caption
mtcars %>% 
    tab_cells(mpg, disp, hp, wt, qsec) %>%
    tab_cols(total(), am) %>% 
    tab_stat_mean_sd_n() %>%
    tab_last_sig_means(subtable_marks = "both") %>% 
    tab_pivot() %>% 
    set_caption("Table with summary statistics and significance marks.")

# Table with the same summary statistics. Statistics labels in columns.
mtcars %>% 
    tab_cells(mpg, disp, hp, wt, qsec) %>%
    tab_cols(total(label = "#Total| |"), am) %>% 
    tab_stat_fun(Mean = w_mean, "Std. dev." = w_sd, "Valid N" = w_n, method = list) %>%
    tab_pivot()

# Different statistics for different variables.
mtcars %>%
    tab_cols(total(), vs) %>%
    tab_cells(mpg) %>% 
    tab_stat_mean() %>% 
    tab_stat_valid_n() %>% 
    tab_cells(am) %>%
    tab_stat_cpct(total_row_position = "none", label = "col %") %>%
    tab_stat_rpct(total_row_position = "none", label = "row %") %>%
    tab_stat_tpct(total_row_position = "none", label = "table %") %>%
    tab_pivot(stat_position = "inside_rows") 

# Table with split by rows and with custom totals.
mtcars %>% 
    tab_cells(cyl) %>% 
    tab_cols(total(), vs) %>% 
    tab_rows(am) %>% 
    tab_stat_cpct(total_row_position = "above",
                  total_label = c("number of cases", "row %"),
                  total_statistic = c("u_cases", "u_rpct")) %>% 
    tab_pivot()

# Linear regression by groups.
mtcars %>% 
    tab_cells(sheet(mpg, disp, hp, wt, qsec)) %>% 
    tab_cols(total(label = "#Total| |"), am) %>% 
    tab_stat_fun_df(
        function(x){
            frm = reformulate(".", response = as.name(names(x)[1]))
            model = lm(frm, data = x)
            sheet('Coef.' = coef(model), 
                  confint(model)
            )
        }    
    ) %>% 
    tab_pivot() 

Example of data processing with multiple-response variables

Here we use truncated dataset with data from product test of two samples of chocolate sweets. 150 respondents tested two kinds of sweets (codenames: VSX123 and SDF546). Sample was divided into two groups (cells) of 75 respondents in each group. In cell 1 product VSX123 was presented first and then SDF546. In cell 2 sweets were presented in reversed order. Questions about respondent impressions about first product are in the block A (and about second tested product in the block B). At the end of the questionnaire there was a question about the preferences between sweets.

List of variables:

data(product_test)

w = product_test # shorter name to save some keystrokes

# here we recode variables from first/second tested product to separate variables for each product according to their cells
# 'h' variables - VSX123 sample, 'p' variables - 'SDF456' sample
# also we recode preferences from first/second product to true names
# for first cell there are no changes, for second cell we should exchange 1 and 2.
w = w %>% 
    let_if(cell == 1, 
        h1_1 %to% h1_6 := recode(a1_1 %to% a1_6, other ~ copy),
        p1_1 %to% p1_6 := recode(b1_1 %to% b1_6, other ~ copy),
        h22 := recode(a22, other ~ copy), 
        p22 := recode(b22, other ~ copy),
        c1r = c1
    ) %>% 
    let_if(cell == 2, 
        p1_1 %to% p1_6 := recode(a1_1 %to% a1_6, other ~ copy), 
        h1_1 %to% h1_6 := recode(b1_1 %to% b1_6, other ~ copy),
        p22 := recode(a22, other ~ copy),
        h22 := recode(b22, other ~ copy), 
        c1r := recode(c1, 1 ~ 2, 2 ~ 1, other ~ copy) 
    ) %>% 
    let(
        # recode age by groups
        age_cat = recode(s2a, lo %thru% 25 ~ 1, lo %thru% hi ~ 2),
        # count number of likes
        # codes 2 and 99 are ignored.
        h_likes = count_row_if(1 | 3 %thru% 98, h1_1 %to% h1_6), 
        p_likes = count_row_if(1 | 3 %thru% 98, p1_1 %to% p1_6) 
    )

# here we prepare labels for future usage
codeframe_likes = num_lab("
    1 Liked everything
    2 Disliked everything
    3 Chocolate
    4 Appearance
    5 Taste
    6 Stuffing
    7 Nuts
    8 Consistency
    98 Other
    99 Hard to answer
")

overall_liking_scale = num_lab("
    1 Extremely poor 
    2 Very poor
    3 Quite poor
    4 Neither good, nor poor
    5 Quite good
    6 Very good
    7 Excellent
")

w = apply_labels(w, 
    c1r = "Preferences",
    c1r = num_lab("
        1 VSX123 
        2 SDF456
        3 Hard to say
    "),

    age_cat = "Age",
    age_cat = c("18 - 25" = 1, "26 - 35" = 2),

    h1_1 = "Likes. VSX123",
    p1_1 = "Likes. SDF456",
    h1_1 = codeframe_likes,
    p1_1 = codeframe_likes,

    h_likes = "Number of likes. VSX123",
    p_likes = "Number of likes. SDF456",

    h22 = "Overall quality. VSX123",
    p22 = "Overall quality. SDF456",
    h22 = overall_liking_scale,
    p22 = overall_liking_scale
)

Are there any significant differences between preferences? Yes, difference is significant.

# 'tab_mis_val(3)' remove 'hard to say' from vector 
w %>% tab_cols(total(), age_cat) %>% 
      tab_cells(c1r) %>% 
      tab_mis_val(3) %>% 
      tab_stat_cases() %>% 
      tab_last_sig_cases() %>% 
      tab_pivot()

Further we calculate distribution of answers in the survey questions.

# lets specify repeated parts of table creation chains
banner = w %>% tab_cols(total(), age_cat, c1r) 
# column percent with significance
tab_cpct_sig = . %>% tab_stat_cpct() %>% 
                    tab_last_sig_cpct(sig_labels = paste0("<b>",LETTERS, "</b>"))

# means with siginifcance
tab_means_sig = . %>% tab_stat_mean_sd_n(labels = c("<b><u>Mean</u></b>", "sd", "N")) %>% 
                      tab_last_sig_means(
                          sig_labels = paste0("<b>",LETTERS, "</b>"),   
                          keep = "means")

# Preferences
banner %>% 
    tab_cells(c1r) %>% 
    tab_cpct_sig() %>% 
    tab_pivot() 

# Overall liking
banner %>%  
    tab_cells(h22) %>% 
    tab_means_sig() %>% 
    tab_cpct_sig() %>%  
    tab_cells(p22) %>% 
    tab_means_sig() %>% 
    tab_cpct_sig() %>%
    tab_pivot() 

# Likes
banner %>% 
    tab_cells(h_likes) %>% 
    tab_means_sig() %>% 
    tab_cells(mrset(h1_1 %to% h1_6)) %>% 
    tab_cpct_sig() %>% 
    tab_cells(p_likes) %>% 
    tab_means_sig() %>% 
    tab_cells(mrset(p1_1 %to% p1_6)) %>% 
    tab_cpct_sig() %>%
    tab_pivot() 

# below more complicated table where we compare likes side by side
# Likes - side by side comparison
w %>% 
    tab_cols(total(label = "#Total| |"), c1r) %>% 
    tab_cells(list(unvr(mrset(h1_1 %to% h1_6)))) %>% 
    tab_stat_cpct(label = var_lab(h1_1)) %>% 
    tab_cells(list(unvr(mrset(p1_1 %to% p1_6)))) %>% 
    tab_stat_cpct(label = var_lab(p1_1)) %>% 
    tab_pivot(stat_position = "inside_columns") 

We can save labelled dataset as *.csv file with accompanying R code for labelling.

write_labelled_csv(w, file  filename = "product_test.csv")

Or, we can save dataset as *.csv file with SPSS syntax to read data and apply labels.

write_labelled_spss(w, file  filename = "product_test.csv")


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expss documentation built on Jan. 7, 2022, 5:23 p.m.