How to replace NA values in a dataframe with Zero s

Question

I have a dataframe which consist of NA values, want to replace that values with zero's?

> as.data.frame(matrix(sample(c(NA, 1:10), 100, replace = TRUE), 10))
   V1 V2 V3 V4 V5 V6 V7 V8 V9 V10
1   9 NA  9 NA NA  6  3 NA  6   8
2   8  8  4  6  9  5  9  4 10   7
3  10  7  7 10  3 NA 10 NA  5  10
4   6  6 NA  9 10  1  4  5 NA   2
5   9  3  3  6  7 10  6  3  2   1
6   4  3  2  5  3 NA  7  7  2   4
7   4  1  8  9  5  1  5  8 NA  NA
8   7  5  4 NA  8 10  3  5  9   2
9   4  3  1  5  5  2  8  3  6   2
10  3 10  3  3  5  6  2 NA  3   4

Answer 1

It is simple and easy:

df1<-as.data.frame(matrix(sample(c(NA, 1:10), 100, replace = TRUE), 10))

df1[is.na(df1)] <- 0
> df1
   V1 V2 V3 V4 V5 V6 V7 V8 V9 V10
1   3  7  1  1  9  2  3  8  7   2
2  10  1  0  5  6  3  9  9  5   1
3   2 10  0  4  4  3  8  9  3   8
4   5  7  2  3  9  4  9  8  2   5
5   5  2  2  3  9 10  6  4  3   7
6   2  4  1  1  5  3  6  4  7  10
7   2  0  2  7  2  4  6  6  7   8
8   2  5  0  2 10  4  2  6  1   3
9   0  3  3  6  7  5  3  3  1   1
10  0  7  1  0  2  2  4  9  4   7

Note*: Here random sample has created new values.