I am trying to replace all the \".\" in a specific column of my data frame with \"/\". There are other characters in each cell and I want to make sure I only change the \".\"\'s
My recommendation would be to escape the "." character:
spy$Identifier <- gsub("\\.", "/", spy$Identifier)
In regular expression, a period is a special character that matches any character. "Escaping" it tells the search to look for an actual period. In R's gsub this is accomplished with two backslashes (i.e.: "\\"). In other languages, it's often just one backslash.