Convert List of Vectors to Data Frame

convert a list of vectors to data frame

An option with base R

do.call(rbind, Map(cbind, lapply(a, stack), P = names(a)))

Convert a list to a data frame

Update July 2020:

The default for the parameter stringsAsFactors is now default.stringsAsFactors() which in turn yields FALSE as its default.

---

Assuming your list of lists is called l:

df <- data.frame(matrix(unlist(l), nrow=length(l), byrow=TRUE))

The above will convert all character columns to factors, to avoid this you can add a parameter to the data.frame() call:

df <- data.frame(matrix(unlist(l), nrow=132, byrow=TRUE),stringsAsFactors=FALSE)

Use bind_rows to convert list of vectors to dataframe

One option could be:

map_dfr(a, ~ set_names(.x, paste0("V", seq_along(.x))))

     V1    V2    V3    V4
  <dbl> <dbl> <dbl> <dbl>
1     1     2     3     4
2     1     2     3     4
3     4     5     6     3
4     6     3     2     6

Convert list of raw-vectors in dataframe

You have to use I when creating the data.frame.

output <- list(raw(2), raw(3))
DF <- data.frame(ID=1:2, vectors = I(output))

str(DF)
#'data.frame':   2 obs. of  2 variables:
# $ ID     : int  1 2
# $ vectors:List of 2
#  ..$ : raw  00 00
#  ..$ : raw  00 00 00
#  ..- attr(*, "class")= chr "AsIs"

DF
#DF
#  ID    vectors
#1  1     00, 00
#2  2 00, 00, 00

How do you convert large list with vectors of different lenght to dataframe?

You could do:

t(as.data.frame(lapply(lst, "length<-", max(lengths(lst)))))

#    [,1] [,2] [,3] [,4] [,5]
#a      1    2    4    5    6
#c      7    8    9   NA   NA
#c.1   10   11   NA   NA   NA

Or as @Andrew pointed out, you can do:

t(sapply(lst, "length<-", max(lengths(lst))))

#  [,1] [,2] [,3] [,4] [,5]
#a    1    2    4    5    6
#c    7    8    9   NA   NA
#c   10   11   NA   NA   NA

Convert list of arrays to pandas dataframe

Option 1:

In [143]: pd.DataFrame(np.concatenate(list_arrays))
Out[143]:
   0  1  2  3  4  5  6  7  8
0  0  0  0  1  0  0  0  0  0
1  0  0  3  2  0  0  0  0  0

Option 2:

In [144]: pd.DataFrame(list(map(np.ravel, list_arrays)))
Out[144]:
   0  1  2  3  4  5  6  7  8
0  0  0  0  1  0  0  0  0  0
1  0  0  3  2  0  0  0  0  0

---

Why do I get:

ValueError: Must pass 2-d input

I think pd.DataFrame() tries to convert it to NDArray like as follows:

In [148]: np.array(list_arrays)
Out[148]:
array([[[0, 0, 0, 1, 0, 0, 0, 0, 0]],

       [[0, 0, 3, 2, 0, 0, 0, 0, 0]]], dtype=uint8)

In [149]: np.array(list_arrays).shape
Out[149]: (2, 1, 9)     # <----- NOTE: 3D array

---

Related Topics