17.1 Find simple matches with grep

• Find a pattern anywhere in the string (outputs the index of the element):

# By default, outputs the index of the element matching the pattern
grep(pattern="Gen", 
    x="Genomics")

• Show actual element where the pattern is found (instead of the index only) with value=TRUE:

# Set value=TRUE
grep(pattern="Gen",
        x="Genomics",
        value=TRUE)

• Non case-sensitive search with ignore.case=TRUE:

# Enter the pattern in lower-case, but case is ignored
grep(pattern="gen",
        x="Genomics",
        value=TRUE,
        ignore.case=TRUE)

• Show if it DOESN’T match the pattern with inv=TRUE:

# Shows what doesn't match
grep(pattern="gen",
        x="Genomics",
        value=TRUE,
        ignore.case=TRUE,
    inv=TRUE)