yy and p should copy and paste 1 line of text.
But I have to go back and delete the original line.
:2,5m10
should move lines from 2 to 5 to line 10. however I need to enable :set number
to see what lines I am moving
I would like to move just 1 line of text, sort of like yy+p and not use :2,3m10
to move just one line.
Is there something like mm+p ?
so it copies the current line into buffer and deletes the line and you p paste it where you want ?
:3m . moves line 3 to your current line.
Above line does the function I want. Can I set a key mapping so
that "mm" replaces ":3m." ? I find it easier to type. TIA
What you're describing is the default behaviour when using dd -it deletes a
line into the buffer and p will paste it.
So dd and p works.
If you're new to vim, then it might seem a little strange that 'yanking' (with
y) and 'deleting' (with d) both copy to the buffer, given the 'cut', 'copy'
and 'paste' behaviours of most other editors.
You can read more about it with :help change.txt and in particular :help registers.
Also, since you say you need to enable :set number, I wonder if you've come
across :set relativenumber? This is very useful - in the example below, the
numbers would look this way if the your cursor was on the line with
'demonstrate':
3 This is just
2 a small
1 example to
0 demonstrate
1 how relative
2 numbers can
3 be useful
Thus if you wanted to move the line 'a small' below the line with 'numbers
can', you could use the relative line numbers to know that 2k would put the
cursor on the line you want, where you'd hit dd, then you'd have this
situation (the deleted line is now in the buffer:
1 This is just
0 example to
1 demonstrate
2 how relative
3 numbers can
4 be useful
Then you can do 3j to move to the 'numbers can' line, and hit p. So
relative numbers are a nice way to move quickly to lines you can see. Also,
just for completeness, you can use relative numbers in a similar way on the
command line::-2m+3 (although I know this isn't what you're after). You can
even set both relative number and set number at the same time, in which case
it's like in the example above, only you have the absolute line number
displayed on the current line instead of a zero.
Related
In Vimium, is there something like f for input fields? E.g. in a form with 10 input fields, I directly want to jump to the 5th, instead of only gi and tabbing through. Is that possible using Vimium?
Yes, as in many shortcuts in vim you can prefix a command with a number. I.e. to jump to the 5th field you type 5gi.
Other vim style examples (It isn't related to vimium. I included it only to illustrate the approach):
3dd delete 3 lines
2j go up 2 lines
5p paste the buffer 5 times
I'm trying to use VHDL to read from a file that can have different formats. I know you're supposed to use the following two lines of code to read a line at a time, the read individual elements in that line.
readline(file, aline);
read(aline, element);
However my question is what will read(aline, element) return into element? What will it return if the line is empty? What will it return if I've used it let's say 5 times and my line only has 4 characters?
The reason I want to know is that if I am reading a file with an arbitrary number of spaces between valid data, how do I parse this valid data?
The file contains ASCII characters separated by arbitrary amounts of white space (any number of spaces, tabs, or new lines). If the line starts with a # that line is a comment and should be ignored.
Outside of these comments, the first part of the file contains characters that are only letters or numbers in combinations of variable size. In other words this:
123 ABC 12ABB3
However, the majority of the file (after a certain number of read words) will be purely numbers of arbitrary length, separated by an arbitrary amount of white space. In other words, the second part of the file is this:
255 0 2245 625 430
2222 33 111111
and I must be able to parse these numbers (and interpret them as such) individually.
As mentioned in the comments, all the read procedures in std.textio and ieee.std_logic_textio skip over leading spaces apart from the character and string versions (because a space is as much a character as any other).
You can test whether a line variable (the buffer) is empty like this:
if L'length > 0 then
where L is your line variable. There is also a set of overloaded read procedures with an extra status output:
procedure read (L : inout LINE;
VALUE: out <type> ;
GOOD : out BOOLEAN);
The extra output - GOOD - is true if the read was successful and false if it wasn't. The advantage of these if that the read is unsuccessful, the simulation does not stop (as it does with the regular procedures). Also, with the versions in std.textio, if the read is unsuccessful, the read is non-destructive (ie whatever you were trying to read remains in the buffer). This is not the case with the versions in ieee.std_logic_textio, however.
If you really do not know what format you are trying to read, you could read the entire line into a string, like this:
variable S : string(1 to <some big number>);
...
readline(F, L);
assert L'length < S'length; -- make sure S is big enough
S := (others => ' '); -- make sure that the previous line is overwritten
if L'length > 0 then
read(L, S(1 to L'length);
end if;
The line L is now in the string S. You can then write some code to parse it. You may find the type attribute 'value useful. This converts a string to some type, eg
variable I : integer;
...
I := integer'value(S(12 to 14));
would set integer I to the value contained in elements 12 to 14 of string S.
Another approach, as suggested by user1155120 below, is to peek at the values in the buffer, eg
if L'length > 0 then -- check that the L isn't empty, otherwise the next line blows up
if L.all(1) = '#' then
-- the first character of the line is a '#' so the line must be a comment
I want to read a particular line of a file, e.g. the 3rd line of the input.dat file. My present code :
Program Read_a_line
Implicit None
Integer:: i
Real*8:: x,y
open (10, file='input.dat', status='old')
do i=1,3
read (10,*) x, y
end do
print*,'x=',x,' y=',y
End Program Read_a_line
However, the code reads all the data till it reaches the 3rd line. Can we just read the 3rd line? Can we read several particular lines, eg. the 2nd and 4th lines only.
Online available examples do a similar trick. I was wondering if there exists a direct way in modern fortran version.
I'm a bit curious!
if you have fixed size records you can seek to the correct point
see also Can I move the file pointer to a particular (byte) location in a formatted file?
How do I fix the Fortran runtime error: Bad integer for item 0 in list input?
Below is the Fortran program which generates a runtime error.
CHARACTER CNFILE*(*)
REAL BOX
INTEGER CNUNIT
PARAMETER ( CNUNIT = 10 )
INTEGER NN
OPEN ( UNIT = CNUNIT, FILE = CNFILE, STATUS = 'OLD' )
READ ( CNUNIT,* ) NN, BOX
The error message received from gdb is :
At line 688 of file MCNPT.f (unit = 10, file = 'LATTICE-256.txt')
Fortran runtime error: Bad integer for item 0 in list input
[Inferior 1 (process 3052) exited with code 02]
(gdb)
I am not sure what options must be specified for READ() to read to numbers from the text file. Does it matter if the two numbers on the same line are specified as either an integer or a real in the text file?
Below is the gdb execution of the program using a break point at the open call
Breakpoint 1, readcn (
cnfile=<error reading variable: Cannot access memory at address 0x7fffffffdff0>,
box=-3.37898272e+33, _cnfile=30) at MCNPT.f:686
Since you did not specify form="unformatted" on the open statement, the unit / file is opened for formatted IO. This is appropriate for a human-readable text file. ("unformatted" would be used for a non-human readable file in computer-native format, sometimes called "binary".) Therefore you should provide a format on the read, or use list-directed read, i.e., read(unit, *). To advise on a particular format we would have to know the layout of the numbers in the file. A possible read with format is: read (CNUINT, '(I4, 2X, F6.2)' ) NN, BOX
P.S. I'm answering the question in your question and not the title, which seems unrelated.
EDIT: now that you are show the text data file, a list-directed read looks easier. That is because the data doesn't line up in columns. It seems that the file has two integers on the first line, then three real numbers on each of the following lines. Most likely you need a different read for the first line. Is the code sample that you are showing us trying to read the first line, or one of the later lines? If the first line, it would seem plausible to read into two integer variables. If a later line, into two or three real variables. Two if you wish to skip the third data item on the line.
EDIT 2: the question has been substantially altered several times, which is very confusing. The first line of the text file that was shown in one version of the question contained integers, with later lines having reals. Since the listed-directed read is reading into an integer and a floating variable, it will have problems if you attempt to use it on the later lines that have two real values.
How do we read a specific file line by line while skipping some columns in it?
For example, I have a text file which has data, sorted out in 5 columns, but I need to read only two columns out of it, they can be first two or any other random combination (I mean, need a solution which would work with any combination of columns like first and third only).
Code something like this
open(1, file=data_file)
read (1,*) ! to skip first line, with metadata
lmax = 0
do while (.true.)
! read column 1 and 3 here, either write
! that to an array or just loop through each row
end do
99 continue
close (1)
Any explanation or example would help a lot.
High Performance Mark's answer gives the essentials of simple selective column reading: one still reads the column but transfers it to a then-ignored variable.
To extend that answer, then, consider that we want to read the second and fourth columns of a five-column line:
read(*,*) junk, x, junk, y
The first value is transferred into junk, then the second into x, then the third (replacing the one just acquired a moment ago) into junk and finally the fourth into y. The fifth is ignored because we've run out of input items and the transfer statement terminates (and the next read in a loop will go to the next record).
Of course, this is fine when we know it's those columns we want. Let's generalize to when we don't know in advance:
integer col1, col2 ! The columns we require, defined somehow (assume col1<col2)
<type>, dimension(nrows) :: x, y, junk(3) ! For the number of rows
integer i
do i=1,nrows
read(*,*) junk(:col1-1), x(i), junk(:col2-col1-1), y(i)
end do
Here, we transfer a number of values (which may be zero) up to just before the first column of interest, then the value of interest. After that, more to-be-ignored values (possibly zero), then the final value of interest. The rest of the row is skipped.
This is still very basic and avoids many potential complications in requirements. To some extent, it's such a basic approach one may as well just consider:
do i=1,nrows
read(*,*) allofthem(:5)
x(i) = allofthem(col1)
y(i) = allofthem(col2)
end do
(where that variable is a row-by-row temporary) but variety and options are good.
This is very easy. You simply read 5 variables from each line and ignore the ones you have no further use for. Something like
do i = 1, 100
read(*,*) a(i), b, c(i), d, e
end do
This will overwrite the values in b, d, and e at every iteration.
Incidentally, your line
99 continue
is redundant; it's not used as the closing line for the do loop and you're not branching to it from anywhere else. If you are branching to it from unseen code you could just attach the label 99 to the next line and delete the continue statement. Generally, continue is redundant in modern Fortran; specifically it seems redundant in your code.