character position in string - string

I have a data frame with character strings in column1 and ID in column2. The string contains A,T,G or C.
I would like to print the lines that have an A at position 1.
Then I would like to print the lines that have A at position 2 and so on and save them in separate files.
So far I have used biostrings in R for similar analysis, but it won't work for this problem exactly. I would like to use perl.
Sequence ID
TATACAAGGGCAAGCTCTCTGT mmu-miR-381-3p
TCGGATCCGTCTGAGCT mmu-miR-127-3p
ATAGTAGACCGTATAGCGTACG mmu-miR-411-5p
......
600 more lines

Biostrings will work perfectly, and will be pretty fast. Let's call your DNA stringset mydata
HasA <- sapply(mydata,function(x) as.character(x[2]) == "A")
Now you have a vector of TRUE or FALSE indicating which sequence has an A at position 2. You can make that into a nice data frame like this
HasA.df <- data.frame("SeqName" = names(mydata), "A_at_2" = HasA)

Not sure about the expected result,
mydata <- read.table(text="Sequence ID
TATACAAGGGCAAGCTCTCTGT mmu-miR-381-3p
TCGGATCCGTCTGAGCT mmu-miR-127-3p
ATAGTAGACCGTATAGCGTACG mmu-miR-411-5p",sep="",header=T,stringsAsFactors=F)
mCh <- max(nchar(mydata[,1])) #gives the maximum number of characters in the first column
sapply(seq(mCh), function(i) substr(mydata[,1],i,i)=="A") #gives the index
You can use which to get the index of the row that satisfies the condition for each position
res <- stack(setNames(sapply(seq(mCh),
function(i) which(substr(mydata[,1],i,i)=="A")),1:mCh))[,2:1]
tail(res, 5) #for the 13th position, 1st and 3rd row of the sequence are TRUE
ind values
#11 13 1
#12 13 3
#13 14 2
#14 15 3
#15 20 3
use the index values to extract the rows. For the 1st position
mydata[res$values[res$ind==1],]
# Sequence ID
# 3 ATAGTAGACCGTATAGCGTACG mmu-miR-411-5p

Using a perl one-liner
perl -Mautodie -lane '
BEGIN {($f) = #ARGV}
next if $. == 1;
my #c = split //, $F[0];
for my $i (grep {$c[$_] eq "A"} (0..$#c)) {
open my $fh, ">>", "$f.$i";
print $fh $_;
}
' file

Related

Analyzing input from an internal unit in fortran [duplicate]

I have specific dataformat, say 'n' (arbitrary) row and '4' columns. If 'n' is '10', the example data would go like this.
1.01e+00 -2.01e-02 -3.01e-01 4.01e+02
1.02e+00 -2.02e-02 -3.02e-01 4.02e+02
1.03e+00 -2.03e-02 -3.03e-01 4.03e+02
1.04e+00 -2.04e-02 -3.04e-01 4.04e+02
1.05e+00 -2.05e-02 -3.05e-01 4.05e+02
1.06e+00 -2.06e-02 -3.06e-01 4.06e+02
1.07e+00 -2.07e-02 -3.07e-01 4.07e+02
1.08e+00 -2.08e-02 -3.08e-01 4.07e+02
1.09e+00 -2.09e-02 -3.09e-01 4.09e+02
1.10e+00 -2.10e-02 -3.10e-01 4.10e+02
Constraints in building this input would be
data should have '4' columns.
data separated by white spaces.
I want to implement a feature to check whether the input file has '4' columns in every row, and built my own based on the 'M.S.B's answer in the post Reading data file in Fortran with known number of lines but unknown number of entries in each line.
program readtest
use :: iso_fortran_env
implicit none
character(len=512) :: buffer
integer :: i, i_line, n, io, pos, pos_tmp, n_space
integer,parameter :: max_len = 512
character(len=max_len) :: filename
filename = 'data_wrong.dat'
open(42, file=trim(filename), status='old', action='read')
print *, '+++++++++++++++++++++++++++++++++++'
print *, '+ Count lines +'
print *, '+++++++++++++++++++++++++++++++++++'
n = 0
i_line = 0
do
pos = 1
pos_tmp = 1
i_line = i_line+1
read(42, '(a)', iostat=io) buffer
(*1)! Count blank spaces.
n_space = 0
do
pos = index(buffer(pos+1:), " ") + pos
if (pos /= 0) then
if (pos > pos_tmp+1) then
n_space = n_space+1
pos_tmp = pos
else
pos_tmp = pos
end if
endif
if (pos == max_len) then
exit
end if
end do
pos_tmp = pos
if (io /= 0) then
exit
end if
print *, '> line : ', i_line, ' n_space : ', n_space
n = n+1
end do
print *, ' >> number of line = ', n
end program
If I run the above program with a input file with some wrong rows like follows,
1.01e+00 -2.01e-02 -3.01e-01 4.01e+02
1.02e+00 -2.02e-02 -3.02e-01 4.02e+02
1.03e+00 -2.03e-02 -3.03e-01 4.03e+02
1.04e+00 -2.04e-02 -3.04e-01 4.04e+02
1.05e+00 -2.05e-02 -3.05e-01 4.05e+02
1.06e+00 -2.06e-02 -3.06e-01 4.06e+02
1.07e+00 -2.07e-02 -3.07e-01 4.07e+02
1.0 2.0 3.0
1.08e+00 -2.08e-02 -3.08e-01 4.07e+02 1.00
1.09e+00 -2.09e-02 -3.09e-01 4.09e+02
1.10e+00 -2.10e-02 -3.10e-01 4.10e+02
The output is like this,
+++++++++++++++++++++++++++++++++++
+ Count lines +
+++++++++++++++++++++++++++++++++++
> line : 1 n_space : 4
> line : 2 n_space : 4
> line : 3 n_space : 4
> line : 4 n_space : 4
> line : 5 n_space : 4
> line : 6 n_space : 4
> line : 7 n_space : 4
> line : 8 n_space : 3 (*2)
> line : 9 n_space : 5 (*3)
> line : 10 n_space : 4
> line : 11 n_space : 4
>> number of line = 11
And you can see that the wrong rows are properly detected as I intended (see (*2) and (*3)), and I can write 'if' statements to make some error messages.
But I think my code is 'extremely' ugly since I had to do something like (*1) in the code to count consecutive white spaces as one space. I think there would be much more elegant way to ensure the rows contain only '4' column each, say,
read(*,'4(X, A)') line
(which didn't work)
And also my program would fail if the length of 'buffer' exceeds 'max_len' which is set to '512' in this case. Indeed '512' should be enough for most practical purposes, I also want my checking subroutine to be robust in this way.
So, I want to improve my subroutine in at least these aspects
Want it to be more elegant (not as (*1))
Be more general (especially in regards to 'max_len')
Does anyone has some experience in building this kind of input-checking subroutine ??
Any comments would be highly appreciated.
Thank you for reading the question.
Without knowledge of the exact data format, I think it would be rather difficult to achieve what you want (or at least, I wouldn't know how to do it).
In the most general case, I think your space counting idea is the most robust and correct.
It can be adapted to avoid the maximum string length problem you describe.
In the following code, I go through the data as an unformatted, stream access file.
Basically you read every character and take note of new_lines and spaces.
As you did, you use spaces to count to columns (skipping double spaces) and new_line characters to count the rows.
However, here we are not reading the entire line as a string and going through it to find spaces; we read char by char, avoiding the fixed string length problem and we also end up with a single loop. Hope it helps.
EDIT: now handles white spaces at beginning at end of line and empty lines
program readtest
use :: iso_fortran_env
implicit none
character :: old_char, new_char
integer :: line, io, cols
logical :: beg_line
integer,parameter :: max_len = 512
character(len=max_len) :: filename
filename = 'data_wrong.txt'
! Output format to be used later
100 format (a, 3x, i0, a, 3x , i0)
open(42, file=trim(filename), status='old', action='read', &
form="unformatted", access="stream")
! set utils
old_char = " "
line = 0
beg_line = .true.
cols = 0
! Start scannig char by char
do
read(42, iostat = io) new_char
! Exit if EOF
if (io < 0) then
exit
end if
! Deal with empty lines
if (beg_line .and. new_char==new_line(new_char)) then
line = line + 1
write(*, 100, advance="no") "Line number:", line, &
"; Columns: Number", cols
write(*,'(6x, a5)') "EMPTYLINE"
! Deal with beginning of line for white spaces
elseif (beg_line) then
beg_line = .false.
! this indicates new columns
elseif (new_char==" " .and. old_char/=" ") then
cols = cols + 1
! End of line: time to print
elseif (new_char==new_line(new_char)) then
if (old_char/=" ") then
cols = cols+1
endif
line = line + 1
! Printing out results
write(*, 100, advance="no") "Line number:", line, &
"; Columns: Number", cols
if (cols == 4) then
write(*,'(6x, a5)') "OK"
else
write(*,'(6x, a5)') "ERROR"
end if
! Restart with a new line (reset counters)
cols = 0
beg_line = .true.
end if
old_char = new_char
end do
end program
This is the output of this program:
Line number: 1; Columns number: 4 OK
Line number: 2; Columns number: 4 OK
Line number: 3; Columns number: 4 OK
Line number: 4; Columns number: 4 OK
Line number: 5; Columns number: 4 OK
Line number: 6; Columns number: 4 OK
Line number: 7; Columns number: 4 OK
Line number: 8; Columns number: 3 ERROR
Line number: 9; Columns number: 5 ERROR
Line number: 10; Columns number: 4 OK
Line number: 11; Columns number: 4 OK
If you knew your data format, you could read your lines in a vector of dimension 4 and use iostat variable to print out an error on each line where iostat is an integer greater than 0.
Instead of counting whitespace you can use manipulation of substrings to get what you want. A simple example follows:
program foo
implicit none
character(len=512) str ! Assume str is sufficiently long buffer
integer fd, cnt, m, n
open(newunit=fd, file='test.dat', status='old')
do
cnt = 0
read(fd,'(A)',end=10) str
str = adjustl(str) ! Eliminate possible leading whitespace
do
n = index(str, ' ') ! Find first space
if (n /= 0) then
write(*, '(A)', advance='no') str(1:n)
str = adjustl(str(n+1:))
end if
if (len_trim(str) == 0) exit ! Trailing whitespace
cnt = cnt + 1
end do
if (cnt /= 3) then
write(*,'(A)') ' Error'
else
write(*,*)
end if
end do
10 close(fd)
end program foo
this should read any line of reasonable length (up to the line limit your compiler defaults to, which is generally 2GB now-adays). You could change it to stream I/O to have no limit but most Fortran compilers have trouble reading stream I/O from stdin, which this example reads from. So if the line looks anything like a list of numbers it should read them, tell you how many it read, and let you know if it had an error reading any value as a number (character strings, strings bigger than the size of a REAL value, ....). All the parts here are explained on the Fortran Wiki, but to keep it short this is a stripped down version that just puts the pieces together. The oddest behavior it would have is that if you entered something like this with a slash in it
10 20,,30,40e4 50 / this is a list of numbers
it would treat everything after the slash as a comment and not generate a non-zero status return while returning five values. For a more detailed explanation of the code I think the annotated pieces on the Wiki explain how it works. In the search, look for "getvals" and "readline".
So with this program you can read a line and if the return status is zero and the number of values read is four you should be good except for a few dusty corners where the lines would definitely not look like a list of numbers.
module M_getvals
private
public getvals, readline
implicit none
contains
subroutine getvals(line,values,icount,ierr)
character(len=*),intent(in) :: line
real :: values(:)
integer,intent(out) :: icount, ierr
character(len=:),allocatable :: buffer
character(len=len(line)) :: words(size(values))
integer :: ios, i
ierr=0
words=' '
buffer=trim(line)//"/"
read(buffer,*,iostat=ios) words
icount=0
do i=1,size(values)
if(words(i).eq.'') cycle
read(words(i),*,iostat=ios)values(icount+1)
if(ios.eq.0)then
icount=icount+1
else
ierr=ios
write(*,*)'*getvals* WARNING:['//trim(words(i))//'] is not a number'
endif
enddo
end subroutine getvals
subroutine readline(line,ier)
character(len=:),allocatable,intent(out) :: line
integer,intent(out) :: ier
integer,parameter :: buflen=1024
character(len=buflen) :: buffer
integer :: last, isize
line=''
ier=0
INFINITE: do
read(*,iostat=ier,fmt='(a)',advance='no',size=isize) buffer
if(isize.gt.0)line=line//buffer(:isize)
if(is_iostat_eor(ier))then
last=len(line)
if(last.ne.0)then
if(line(last:last).eq.'\\')then
line=line(:last-1)
cycle INFINITE
endif
endif
ier=0
exit INFINITE
elseif(ier.ne.0)then
exit INFINITE
endif
enddo INFINITE
line=trim(line)
end subroutine readline
end module M_getvals
program tryit
use M_getvals, only: getvals, readline
implicit none
character(len=:),allocatable :: line
real,allocatable :: values(:)
integer :: icount, ier, ierr
INFINITE: do
call readline(line,ier)
if(allocated(values))deallocate(values)
allocate(values(len(line)/2+1))
if(ier.ne.0)exit INFINITE
call getvals(line,values,icount,ierr)
write(*,'(*(g0,1x))')'VALUES=',values(:icount),'NUMBER OF VALUES=',icount,'STATUS=',ierr
enddo INFINITE
end program tryit
Honesty, it should work reasonably with just about any line you throw at it.
PS:
If you are always reading four values, using list-directed I/O and checking the iostat= value on READ and checking if you hit EOR would be very simple (just a few lines) but since you said you wanted to read lines of arbitrary length I am assuming four values on a line was just an example and you wanted something very generic.

looping through two files and count string occurrences of 2nd file in lines of first file using python

Thank you for your help and Apologies for my naiveness
I need to generate permutation of some words (A T G C ) actually nucleotides for di-composition (eg AA AT AG AC), tri-composition (AAA AAT AAC AAG), tetra, penta etc (one at a time) and then check in the other file that contains sequences with some values the count of occurrences of each permutation. I generated the permutation list.
Now I need to loop through the sequences only (splitting the sequences from values) for counting each of the permutation generated above and get the output in new file.
But I'm getting the answer for only one sequence and not for the other sequences.
Logic of the programme i tried to follow is :
Generate the permutations of ATCG in a file1 (e.g. AT AG AC AA ...)
Read the generated file1 and sequence#value file (DNA_seq_val.txt)
Read the sequences and separate the sequences form values
Loop through the sequences for the permutations and print their
occurrence with values (each separated with comma) in results file.
Input test file= DNA_seq_val.txt
AAAATTTT#99 \n
CCCCGGGG#77\n
ATATATCGCGCG#88\n
*Output I got is --
2,0,0,1,0,0,0,0,0,0,0,0,0,0,0,2,99 AAAATTTT \n
77 CCCCGGGG\n
88 ATATATCGCGCG
Output Needed is
2,0,0,1,0,0,0,0,0,0,0,0,0,0,0,2,99 AAAATTTT \n
x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,77 CCCCGGGGx \n
x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,88 ATATATCGCGCG (where x= corresponding counts as in first line)
enter code herefrom itertools import product
import os
f2 = open('TRYYY', 'a')
#********Generate the permutations start********
per = product('ACGT', repeat=2) # ATGC =nucleotides; 2= for di ntd(replace 2 with 3 fir tri ntds and so on)
f = open('myfile', 'w')
p = ""
for p in per:
p = "".join(p)
f.write(p + "\n")
f.close()
#********Generate the permutations ENDS********
with open('DNA_seq_val.txt', 'r+') as SEQ, open('myfile', 'r+') as TET: #open two files
SEQ_lines = sum(1 for line in open('DNA_seq_val.txt')) #count lines in sequences file
#print (SEQ_lines)
compo_lines = sum(1 for line in open('myfile')) #count lines in composition
#print (compo_lines)
for lines in SEQ:
line,val1 = lines.split("#")
val2 = val1.rstrip('\n')
val = str(val2)
line = line.rstrip('\n')
length =len(line)
#print (line)
#print (val)
LIN = line, val
#print (LIN)
newstr = "".join((line))
print (newstr)
#while True: # infinte loop
for PER in TET:
#print (line)
PER = PER.rstrip('\n')
length2 =len(PER)
#print (length2)
#print (line)
# print (PER)
C_PER = str(line.count(PER))
# print (C_PER)
for R in C_PER:
R1 = "".join(R)
f2.write(R1+ ",")
f2.write(val,)
f2.write('\t')
f2.write(line)
f2.write('\n')
#exit()

How to Print a string to a specific character?

I have a file like this:
NA|polymerase|KC545393|Bundibugyo_ebolavirus|EboBund_112_2012|NA|2012|Human|Democratic_Republic_of_the_Congo
NA|VP24|KC545393|Bundibugyo_ebolavirus|EboBund_112_2012|NA|2012|Human|Democratic_Republic_of_the_Congo
NA|VP30|KC545393|Bundibugyo_ebolavirus|EboBund_112_2012|NA|2012|Human|Democratic_Republic_of_the_Congo
I am trying to print this characters from each line:
polymerase|KC545393
VP24|KC545393
VP30|KC545393
How can I do this?
I tried this code:
for character in line:
if character=="|":
print line[1:i.index(j)]
Use str.split() to split each line by the '|' character; you can limit the splitting because you only need the first 3 columns:
elems = line.split('|', 3)
print '|'.join(elems[1:3])
The print line then takes the elements at index 1 and 2 and joins them together again using the '|' character to produce your desired output.
Demo:
>>> lines = '''\
... NA|polymerase|KC545393|Bundibugyo_ebolavirus|EboBund_112_2012|NA|2012|Human|Democratic_Republic_of_the_Congo
... NA|VP24|KC545393|Bundibugyo_ebolavirus|EboBund_112_2012|NA|2012|Human|Democratic_Republic_of_the_Congo
... NA|VP30|KC545393|Bundibugyo_ebolavirus|EboBund_112_2012|NA|2012|Human|Democratic_Republic_of_the_Congo
... '''.splitlines(True)
>>> for line in lines:
... elems = line.split('|', 3)
... print '|'.join(elems[1:3])
...
polymerase|KC545393
VP24|KC545393
VP30|KC545393
Assuming you know that each line has at least two separators, you can use:
>>> s = 'this|is|a|string'
>>> s
'this|is|a|string'
>>> s[:s.find('|',s.find('|')+1)]
'this|is'
This finds the first | starting at the character position beyond the first | (i.e., it finds the second |) then gives you the substring up but not including to that point.
If it may not have two separators, you just have to be more careful:
s = 'blah blah'
result = s
if s.find('|') >= 0:
if s.find('|',s.find('|')+1) >= 0:
result = s[:s.find('|',s.find('|')+1)]
If that's the case, you'll probably definitely want it in a more general purpose function, something like:
def substringUpToNthChar(str,n,ch):
if n < 1: return ""
pos = -1
while n > 0:
pos = str.find(ch,pos+1)
if pos < 0: return str
n -= 1
return str[:pos]
This will correctly handle the case where there's fewer separators than desired and will also handle (relatively elegantly) getting more than the first two fields.

AWK reporting duplicate lines and count, program explanation

I found the following AWK program on the internet and tweaked it slightly to look at column $2:
{ a[$2,NR]=$0; c[$2]++ }
END {
for( k in a ) {
split(k,b,SUBSEP)
t=c[b[1]] # added this bit to capture count
if( b[1] in c && t>1 ) { # added && t>1 only print if count more than 1
print RS "TIMES ID" RS c[b[1]] " " b[1] RS
delete c[b[1]]
}
for(i=1;i<=NR;i++) if( a[b[1],i] ) {
if(t>1){print a[b[1],i]} # added if(t>1) only print lines if count more than 1
delete a[b[1],i]
}
}
}
Given the following file:
abc,2,3
def,3,4
ghi,2,3
jkl,5,9
mno,3,2
The output is as follows when the command is run:
Command: awk -F, -f find_duplicates.awk duplicates
Output:
TIMES ID
2 2
abc,2,3
ghi,2,3
TIMES ID
2 3
def,3,4
mno,3,2
This is fine.
I would like to understand what is happening in the AWK program.
I understand that the first line is loading each line into a multidimentional array ?
So first line of file would be a['2','1']='abc,2,3' and so on.
However I'm a bit confised as to what c[$2]++ does, and also what is the significance of split(k,b,SUBSEP) ??
Would appreciate it if someone could explain line by line what is going on in this AWK program.
Thanks.
The increment operator simply adds one to the value of the referenced variable. So c[$2]++ takes the value for c[$2] and adds one to it. If $2 is a and c["a"] was 3 before, its value will be 4 after this. So c keeps track of how many of each $2 value you have seen.
for (k in a) loops over the keys of a. If the value of $2 on the first line was "a", the first value of k will be "a","1" (with 1 being the line number). The next time, it will be the combination of the value of $2 from the second line and the line number 2, etc.
The split(k,b,SUBSEP) will create a new array b from the compound value in k, i.e. basically reconstruct the parts of the compound key that went into a. The value in b[1] will now be the value which was in $2 when the corresponding value in a was created, and the value in b[2] will be the corresponding line number.
The final loop is somewhat inefficient; it loops over all possible line numbers, then skips immediately to the next one if an entry for that ID and line number did not exist. Because this runs inside the outer loop for (k in a) it will be repeated a large number of times if you have a large number of inputs (it will loop over all input line numbers for each input line). It would be more efficient, at the expense of some additional memory, to just build a final output incrementally, then print it all after you have looped over all of a, by which time you have processed all input lines anyway. Perhaps something like this:
END {
for (k in a) {
split (k,b,SUBSEP)
if (c[b[1]] > 1) {
if (! o[b[1]]) o[b[1]] = c[b[1]] " " b[1] RS
o[b[1]] = o[b[1]] RS a[k]
}
delete a[k]
}
for (q in o) print o[q] RS
}
Update: Removed the premature deletion of c[b[1]].

How do I read a delimited file with strings/numbers with Octave?

I am trying to read a text file containing digits and strings using Octave. The file format is something like this:
A B C
a 10 100
b 20 200
c 30 300
d 40 400
e 50 500
but the delimiter can be space, tab, comma or semicolon. The textread function works fine if the delimiter is space/tab:
[A,B,C] = textread ('test.dat','%s %d %d','headerlines',1)
However it does not work if delimiter is comma/semicolon. I tried to use dklmread:
dlmread ('test.dat',';',1,0)
but it does not work because the first column is a string.
Basically, with textread I can't specify the delimiter and with dlmread I can't specify the format of the first column. Not with the versions of these functions in Octave, at least. Has anybody ever had this problem before?
textread allows you to specify the delimiter-- it honors the property arguments of strread. The following code worked for me:
[A,B,C] = textread( 'test.dat', '%s %d %d' ,'delimiter' , ',' ,1 )
I couldn't find an easy way to do this in Octave currently. You could use fopen() to loop through the file and manually extract the data. I wrote a function that would do this on arbitrary data:
function varargout = coltextread(fname, delim)
% Initialize the variable output argument
varargout = cell(nargout, 1);
% Initialize elements of the cell array to nested cell arrays
% This syntax is due to {:} producing a comma-separated
[varargout{:}] = deal(cell());
fid = fopen(fname, 'r');
while true
% Get the current line
ln = fgetl(fid);
% Stop if EOF
if ln == -1
break;
endif
% Split the line string into components and parse numbers
elems = strsplit(ln, delim);
nums = str2double(elems);
nans = isnan(nums);
% Special case of all strings (header line)
if all(nans)
continue;
endif
% Find the indices of the NaNs
% (i.e. the indices of the strings in the original data)
idxnans = find(nans);
% Assign each corresponding element in the current line
% into the corresponding cell array of varargout
for i = 1:nargout
% Detect if the current index is a string or a num
if any(ismember(idxnans, i))
varargout{i}{end+1} = elems{i};
else
varargout{i}{end+1} = nums(i);
endif
endfor
endwhile
endfunction
It accepts two arguments: the file name, and the delimiter. The function is governed by the number of return variables that are specified, so, for example, [A B C] = coltextread('data.txt', ';'); will try to parse three different data elements from each row in the file, while A = coltextread('data.txt', ';'); will only parse the first elements. If no return variable is given, then the function won't return anything.
The function ignores rows that have all-strings (e.g. the 'A B C' header). Just remove the if all(nans)... section if you want everything.
By default, the 'columns' are returned as cell arrays, although the numbers within those arrays are actually converted numbers, not strings. If you know that a cell array contains only numbers, then you can easily convert it to a column vector with: cell2mat(A)'.

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