How to find and replace double quotes in R data frame - r

Question

I have a data frame that looks like this (sorry, I can't replicate the actual data frame with code as the double quotes don't show up. Vx are variables):
V1, V2, V3, V4
home, 15, "grand", terminal,
"give", 32, "cuz", good,
"miles", 5, "before", ten,
yes, 45, "sorry," fine
Question: how I might be able to fix the double quote issue for my entire data frame that I've imported using the read.csv function, where all the double quotes are removed?
What I'm looking for is the excel or word equivalent of FIND + REPLACE: Find the double quote, and replace with nothing.
Notes:
1) I've confirmed it's a data frame by running is.data.frame() function
2) The actual data frame has hundreds of columns, so going through each one and declaring the type of column it is isn't feasible
3) I tried using the following, and it didn't work: as.data.frame(sapply(my_data, function(x) gsub("\"", "", x)))
4) I confirmed that this isn't a simple print issue by testing using sql on the the data frame. It won't find columns in double quotes unless I use LIKE instead of =
Thanks in advance!
7/7/15 EDIT 01: as requested from #alexforrence, here is the d(put) output for a couple of columns:
billing_first_name billing_last_name billing_company
3 NA
4 Peldi Guilizzoni NA
5 NA
6 "James Andrew" Angus NA
7 NA
8 Nova Spivack NA

Answer 1

Here is a solution using dplyr and stringr. Note that purely numerical columns will be character columns afterwards. It's not clear to me from your description whether there are purely numerical columns. If there are then you'd probably want to treat them separately, or alternatively convert back into numbers afterwards.
require(dplyr)
require(stringr)
df <- data.frame(V1=c("home", "\"give\"", "\"miles\"", "yes"),
V2=c(15, 32, 5, 45),
V3=c("\"grand\"", "\"cuz\"", "\"before\"", "\"sorry\""),
V4=c("terminal", "good", "ten", "fine"))
df
## V1 V2 V3 V4
## 1 home 15 "grand" terminal
## 2 "give" 32 "cuz" good
## 3 "miles" 5 "before" ten
## 4 yes 45 "sorry" fine
df %>% mutate_each(funs(str_replace_all(., "\"", "")))
## V1 V2 V3 V4
## 1 home 15 grand terminal
## 2 give 32 cuz good
## 3 miles 5 before ten
## 4 yes 45 sorry fine

Answer 2

You can identify the double quotes using nchar().
a <- ""
nchar(a)==0
[1] TRUE

Answer 3

In addition to the above I ran into a very strange problem. Using the tips I wrote this very short program:
setClass("char.with.deleted.quotes")
setAs("character", "char.with.deleted.quotes",
function(from) as.character(gsub('„',"xxx", as.character(from), fixed = TRUE)))
TMP = read.csv2("./test.csv", header=TRUE, sep=";", dec=",",
colClasses = c("character","char.with.deleted.quotes"))
temp <- gsub('„', "xxx", TMP$Name, fixed=TRUE)
print(temp)
with the Output:
> source('test.R')
[1] "This is some „Test" "And another „Test"
[1] " "
Number Name
1 X-23 This is some „Test
2 K-33.01 And another „Test
which reads the dummy csv:
Number;Name
X-23;This is some „Test
K-33.01;And another „Test
My goal is to get rid of this double quote before the word Test. However this so far does not work. And this is because of this double quote.
If instead I choose to replace a different part of the character it does work with either read.csv2 and the above definition of a class or directly with gsub saving it into the temp variable.
Now what is really strange is the following. After running the program I copied the two lines "temp <- gsub" and "print(temp)" manually into the command line:
> source('test.R')
[1] "This is some „Test" "And another „Test"
[1] "This is some „Test" "And another „Test"
[1] " "
Number Name
1 X-23 This is some „Test
2 K-33.01 And another „Test
>
> temp <- gsub('„', "xxx", TMP$Name, fixed=TRUE)
> print(temp)
[1] "This is some xxxTest" "And another xxxTest"
This for whatever reason works and it does also work if I modify the data frame directly:
> TMP$Name <- gsub('„', "xxx", TMP$Name, fixed=TRUE)
> print(TMP)
Number Name
1 X-23 This is some xxxTest
2 K-33.01 And another xxxTest
But if I repeat this command in the program and run it again, it does not work. And I really have no idea why.