accessing-elements-in-rarrange-fnclasses-in-rdata-types-in-rdataframe-in-rdefault-datasetsfactor-fnflitersif-else-statementsindexingjoinslist-vector-matrix-arraymathematical-operatorsrepeat-functionscatter-histogram-boxplot-pairsselect-fnsequence-functionvariablesvisualizations-in-r