I am trying to solve this challenge on HackerRank:
https://www.hackerrank.com/challenges/30-operators?h_r=next-challenge&h_v=zen
the way I tried to read the stdin is this:
let input = readline()!
However, the input consists of three lines, e.g.
12.00
20
8
How do I get all three lines, ideally in some separated way so that I can cast them to their respective types?
If you need the 3 lines, call it 3 times :)
The documentation is explicit
Returns Characters read from standard input through the end of the
current line or until EOF is reached, or nil if EOF has already been
reached.
But it seems they forgot to indicate that reading a line will change the current line
Generally what I would do is use input() to assign the stdin values to a variable and then pass the variables for functions.
example:
a = input() #gives the first line
b = input() #gives the second line
c = input() #gives the third line
if you would like to read all the lines then use a for loop:
example:
import sys
for line in sys.stdin:
print(line)
Related
I have a substitution to make in a Perl script, which I do not seem to get working. I have a string in a text file which has the form:
T+30H
The string T+30H has to be written in many files and has to change from file to file. It is two digits and sometimes three digits. First I define the variable:
my $wrffcr=qr{T+\d+H};
After reading the file containing the string, I have the following substitution command (starting with the file capture)
#scrptlines=<$NCLSCRPT>;
foreach $scrptlines (#scrptlines) {
$scrptlines =~ s/$wrffcr/T+$fcrange2[$jj]H/g;
}
$fcrange2[$jj] is defined and I confirm its value by printing its value just before the above 4 lines of code.
print "$fcrange2[$jj]\n";
When I run my script, nothing changes for this particular substitution. I suspect it is to do with the way I define the string to be substituted.
I will appreciate any assistance.
Zilore Mumba
Watch out for the first + in my $wrffcr=qr{T+\d+H};. It'll make it match 1 or more Ts, not T followed by a +. You probably want
my $wrffcr=qr{T\+\d+H};
I am trying to take a user input and write it to a separate .txt file with only one input per line.
vote = input()
fh = open('votedata.txt', 'a')
fh.write(vote)
fh.close
When I run my code it saves the input and places it in the txt file, however instead of placing each value on a new line it bunches them together on one. So if I have 5 inputs like 1,2,3,4,5 instead of placing each number on a separate line it bunches them together like 12345. How do I change this?
Try it like this :
vote = input('Enter your vote')
fh = open('votedata.txt', 'a')
fh.write(vote + '\n')
fh.close
I have below function:
function [] = Write(iteration)
status=close('all');
nomrep=num2str(iteration);
fid=fopen('ID.dat','a');
frewind(fid);
for l=1:iteration
line=fgetl(fid);
end
fprintf(fid,[nomrep,' \n']);
status=fclose(fid);
end
I expect that Write(15) creates ID.dat and prints 2 and 15 in consecutive lines at begining of line 15th.
But is prints those values always on the beginning of the file.
Even I tried fgetl(fid) alone, and also replaced for loop with while loop still did not work.
Is it due to the fact that I should fill in the lines before that with some dummy space? along side this, I executed
for i=1:5
Write(i);
end
Which should print 1 to 5 in each line but even this does not work.
This line is the problem:
fid=fopen('ID.dat','w');
Everytime you open the file, you are overwriting the previous contents (that is what the 'w' argument does). Change 'w' to 'a' (for append), and your file will retain the contents from one write to the next.
I'm trying to export a matrix f that is double. My data in f are real numbers in three columns. I want a txt file as an output with the columns separated by tabs. However, when I try the dlmwrite function, just the first column appears as output.
for k = 1:10
f = [idx', firsttime', sectime'];
filename = strcat(('/User/Detection_rerun/AF_TIMIT/1_state/mergedlabels_train/'),(files_train{k,1}),'.lab');
dlmwrite(filename,f,'\t') ;
end
When I use dlmwrite(filename,f,'\t','newline','pc') ; I keep getting an error Invalid attribute tag: \t . I even tried 'tab' instead of '\t' but a similar error appears. Please let me know if you have any suggestions. thank you
This is because you are not calling dlmwrite properly. To specify the delimiter, you must use the delimiter flag, followed by the specific delimiter you want. In your case, you use \t. In other words, you need to do this:
for k = 1:10
f = [idx', firsttime', sectime'];
filename = strcat(('/User/Detection_rerun/AF_TIMIT/1_state/mergedlabels_train/'),(files_train{k,1}),'.lab');
dlmwrite(filename,f,'delimiter','\t') ;
end
BTW, you are using the newline flag with pc, meaning that you are specifying carriage returns that are recognized by a PC. I suggest you leave this out and allow MATLAB to automatically infer this. Only force the newline characters if you know what you're doing.
FWIW, the MATLAB documentation is pretty clear about delimiters and other quirks about the function: http://www.mathworks.com/help/matlab/ref/dlmwrite.html
I am writing a Matlab function that does some file manipulation as follows. I take the input file, read it line by line and write it to an output file. If the line contains a keyword, I do some further processing before writing the output. My problem is this: If the input line contains an escape character, it messes up the fprintf that I use to write the output. For example, if the input line contains a % sign, the rest of the line does not show up in the output. So, my question is: is there a way to force fprintf to ignore all escape sequences and print the literal string? Thanks in advance for the help.
Sample code below:
fptr_read = fopen('read_file.txt','r'); fptr_write = fopen('write_file.txt','w');
while(~feof(fptr_read))
current_line = fgetl(fptr_read);
fprintf(fptr_write,current_line);
end
If current_line looks like 'Gain is 5% larger', it will get written as 'Gain is 5'. I want the line reproduced verbatim without manually having to check for presence of escape characters.
I had a similar problem once, and solved it like this:
fprintf(fp,'%s',stringWithEscapesIWant)