When I type
round(1122700.625, 2)
I get 1122701
when I would expect 1122700.62 from my reading of ?round (nearest even)
Somewhat similarly for
round(205290.125, 2)
I get 205280.1
when I would expect 205290.12
round(205290.125,3) and round(205290.125,4) both give 205290.1
round(2.125, 2) gives 2.12 as expected
and
round(22222.125, 2) gives 22222.12 as expected
but round(222222.125, 2) gives 222222.1
and round(2222222.125, 2) gives 2222222
I have tried running R from the command line with --vanilla option with the same result (originally noted when using RStudio).
The help does also state "The realities of computer arithmetic can cause unexpected results" but
Am I missing something/what don't I understand?
Does this matter?!
I guess you looking for toFixed because the round only expect one param.
CLICK for ref.
Related
I am new to sage and have got a code (link to code) which should run.
I am still getting an error message in the decoding part. The error trace looks like this:
in decode(y)
--> sigma[i+1+1] = sigma[i+1]*(z)\
-(delta[i+1]/delta[mu+1])*z^(i-mu)*sigma[mu+1]*(z);
in sage.structure.element.Element.__mul__
if BOTH_ARE_ELEMNT(cl):
--> return coercion_model.bin_op(left, right, mul)
in sage.structure.coerce.CoercionModel_cache_maps.bin_op
--> action = self.get_action(xp,yp,op,x,y)
...... some more traces (don't actually know if they are important)
TypeError: positive characteristics not allowed in symbolic computations
Does anybody know if there is something wrong in this code snipped? Due to previous errors, I changed the following to get to where I am at the moment:
.coeffs() changed to .coefficients(sparse=False) due to a warning message.
in the code line sigma[i+1+1] = sigma[i+1](z)\
-(delta[i+1]/delta[mu+1])*z^(i-mu)*sigma[mu+1](z); where the error occurs, i needed to insert * eg. sigma[i+1]*(z)
I would be grateful for any guess what could be wrong!
Your issue is that you are multiplying things not of characteristic zero (like elements related to Phi.<x> = GF(2^m)) with elements of symbolic computation like z which you have explicitly defined as a symbolic variable
Phi.<x> = GF(2^m)
PR = PolynomialRing(Phi,'z')
z = var('z')
Basically, the z you get from PR is not the same one as from var('z'). I recommend naming it something else. You should be able to access this with PR.gen() or maybe PR(z).
I'd be able to be more detailed, but I encourage you next time to paste a fully (non-)working example; trying to slog through a big worksheet is not the easiest thing to track all this down. Finally, good luck, hope Sage ends up being useful for you!
i try to run:
x = (1 / 1 – 2)
And here is the message:
Error: unexpected input in "x=(1 / 1 �"
I have the same issue with these sign : <- and * and minus, none of them are recognised.
You might be confronted to the so-called "zero-width space" which is not interpreted as a space. Check this wiki page:
If the blanks you have in your code example are this kind of character, it will make an error like this:
Error: unexpected input in "x=(1 / 1"
as some comments point out, one must be careful when pasting code from websites.
I am learning from the book Learn Python The Hard Way 3.6, by Zed Shaw
There are a series of 6 target.write commands towards the bottom of the script and he wants me to simplify them into a single target.write command using strings formats and escapes. However, I am stuck.
Here is the original code:
from sys import argv
script, filename = argv
print(f"We're going to erase {filename}")
print("If you don't want that, hit CTRL-C (^C).")
print("If you do want that, hit RETURN.")
input("?")
print("Opening the file...")
target = open(filename,'w')
print("Truncating the file. Goodbye!")
target.truncate()
print("Now I'm going to ask you for three lines")
line1 = input("line 1:")
line2 = input("line 2:")
line3 = input("line 3:")
print("Im going to write these to the file.")
target.write(line1)
target.write("\n")
target.write(line2)
target.write("\n")
target.write(line3)
target.write("\n")
print("And finnaly, we close it")
target.close()
So far I have tried
target.write(line1),(line2),(line3)
but this gives a logical error of only writing to one line not all three.
target.write(line1) + (line2) + (line3)
with this one I get error
'unsupported operand types for +: 'int' + 'str'
target.write(line1),\n,(line2)\n(line3),\n
with this one I get error:
unexpected character after line continuation character
(<string>,line 22)
I have been googling and searching here for answers but have not found anything. One person posted a very similar question except for Zed's 2.7 book. However I am reading Zed's 3.6 book so the answers were no help to me unfortunately.
I'm not sure what you have and haven't covered so far in the book as I'm not familiar with it but one way to do what you want is to format the string first and then pass it to the write method like this:
target.write("{0}\n{1}\n{2}\n".format(line1, line2, line3))
Please see below my reference to a previous question asked along these lines.
I am running the library taxize in R. Taxize includes a function for getting a stable number associated with a scientific name, get_tsn().
I can run this in interactive mode or non-interactive mode so that I am either
prompted or not, respectively, to choose among multiple hits.
Interactive:
> tax.num <- get_tsn("Acer rubrum", ask=TRUE)
Retrieving data for taxon 'Acer rubrum'
tsn target commonNames nameUsage
1 28728 Acer rubrum red maple accepted
2 28730 Acer rubrum ssp. drummondii NA not accepted
3 526853 Acer rubrum var. drummondii Drummond's maple accepted
...
More than one TSN found for taxon 'Acer rubrum'!
Enter rownumber of taxon (other inputs will return 'NA'):
Non-interactive:
> tax.num <- get_tsn("Acer rubrum", ask=TRUE)
Retrieving data for taxon 'Acer rubrum'
Warning message:
> 1 result; no direct match found
I need to run this library in interactive mode so that I do not get an empty result when there is more than one match. However, babysitting this script is totally unrealistic for the size of my data, which are in the millions of scientific names. Thus, I want to automate a response to the prompt so that the answer is always 1. This will be the right answer for probably 99% of cases and will ultimately still lead to the right answer downstream in 100% of cases for reasons that are probably beyond the scope of this question.
Thus, how can I automate the response to always be 1?
I looked at this question and tried modifying my code accordingly.
options(httr_oauth_cache=T)
tax.num <- get_tsn("Acer rubrum",ask=T)
However, this gave the same result shown for interactive mode above.
Your help is appreciated.
UPDATE: Ignore below. Obviously Nathan Werth posted the best answer in a comment above.
tax.num <- get_tsn_(searchterm = "Acer rubrum", rows = 1)
works wonderfully!
...
I decided to modify the source code to handle this. I suspect that there is a more desirable solution, but this one meets my needs.
Thus, in the file get_tsn.R from the source, I replaced the following block of code
# prompt
message("\n\n")
print(tsn_df)
message("\nMore than one TSN found for taxon '", x, "'!\n
Enter rownumber of taxon (other inputs will return 'NA'):\n")
# prompt
take <- scan(n = 1, quiet = TRUE, what = 'raw')
with
take <- 1
I could have deleted other echoing to screen bits, that are unnecessary and now not true.
The revised function, which I tested using trace("get_tsn",edit=TRUE), returns as follows:
> print(tax.num)
[1] "28728"
attr(,"match")
[1] "found"
attr(,"multiple_matches")
[1] TRUE
attr(,"pattern_match")
[1] FALSE
attr(,"uri")
[1] "http://www.itis.gov/servlet/SingleRpt/SingleRpt?
search_topic=TSN&search_value=28728"
attr(,"class")
[1] "tsn"
I will recompile and install it on Linux now with the edit for use with this particular project.
I still welcome other, better answers.
I have a fairly basic data.table in R, with 250k rows and 90 columns. I am trying to key the data.table on one of the columns which is of class character. When I call:
setkey(my.dt,my.column)
I receive the following cryptic error message:
"Error in setkeyv(x, cols, verbose=verbose) :
reorder received irregular lengthed list"
I have found a source-code commit with this message, but can't quite decipher what it means. My key column contains no NA or blank values, seems perfectly reasonable to look at (it contains stock tickers), and behaves well with the default order() command.
Even more frustrating, the following code completes correctly:
first.dt <- my.dt[1:100000]
setkey(first.dt,my.column)
second.dt <- my.dt[100001:nrow(my.dt]
setkey(second.dt,my.column)
I have no idea what could be going on here. Any tips?
Edit 1: I have confirmed every value in the key fits a fairly standard format:
> length(grep("[A-Z]{3,4}\\.[A-Z]{2}",my.dt$my.column)) == nrow(my.dt)
[1] TRUE
Edit 2: My system info is below (note that I'm actually using Windows 7). I am using data.table version 1.8.
> Sys.info()
sysname release version nodename machine login
"Windows" "Server 2008 x64" "build 7600" "WIN-9RH28AH0CKG" "x86-64" "Administrator"
user effective_user
"Administrator" "Administrator"
Please run :
sapply(my.dt, length)
I suspect that one or more columns have a different length to the first column, and that's an invalid data.table. It won't be one of the first 5 because your .Internal(inspect(my.dt)) (thanks) shows those and they're ok.
If so, there is this bug fix in v1.8.1 :
o rbind() of DT with an irregular list() now recycles the list items
correctly, #2003. Test added.
Any chance there's an rbind() at an earlier point to create my.dt together with an irregular lengthed list? If not, please step through your code running the sapply(my.dt,length) to see where the invalidly lengthed column is being created. Armed with that we can make a work around and also fix the potential bug. Thanks.
EDIT :
The original cryptic error message is now improved in v1.8.1, as follows :
DT = list(a=6:1,b=4:1)
setattr(DT,"class",c("data.table","data.frame"))
setkey(DT,a)
Error in setkeyv(x, cols, verbose = verbose) :
Column 2 is length 4 which differs from length of column 1 (6). Invalid
data.table. Check NEWS link at top of ?data.table for latest bug fixes. If
not already reported and fixed, please report to datatable-help.
NB: This method to create a data.table is not recommended because it lets you create an invalid data.table. Unless, you are really sure the list is regular and you really do need speed (i.e. for speed you want to avoid the checks that as.data.table() and data.table() do), or you need to demonstrate an invalid data.table, as I'm doing here.