Is there a way to set significant digit display in a flextable?

[davidgohel]

Original question

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I am trying to set significant digit display for a flextable table object.

# Select data from a dataframe
ft <- flextable(data, col_keys = c(1,2,3,4)) 
# adjust digit display in columns 3 and 4 of flextable
ft <- colformat_num(ft, j = c(3,4), digits = 4)

However, the digits argument in this snippet sets digits after the decimal point, as opposed to rounding a number to n significant digits. Here is a sample formula from Excel:

=ROUND(number,digits-(1+INT(LOG10(ABS(number)))))

Can this be reproduced in the flextable command?

[davidgohel]

Use colformat_double(digits = ...)

library(flextable)
ft <- flextable(head(iris)) 
ft <- colformat_double(ft, j = c(3, 4), digits = 4)
ft