I have problem to save array to file, I don't now way I always getting ',' separator in new file that I assuming means new row in array. So for example I have file
this is file
with text
to check
I read this file save to array make some modification and then I want to save this file.
fs.writeFile('to_save', file.map(function(x){return x + '\n'}));
When I do like that I always getting new file with ,
,this is file
,with text
,to check
when I try to remove firs letter using
fs.writeFile('to_save', file.map(function(x){return x = x.substring(1, x.length) + '\n'}));
It remove me t, w and t, so my question is how to get ride this separator?
Use join instead of map
fs.writeFile('to_save', file.join("\n"));
writeFile expects a string, a buffer, or an Uint8Array as data. It will implicitly call toString() on an array, which is why you'll get the commas.
Related
I've a text file which I'll be using it to write content.. But every time before I write something to the file, I wish to clear the content without deleting the file..
How would I achieve the above? Any suggestions?
With text files you can simply set it to an empty string.
file.text = ''
I would use the setBytes method on java.io.File and provide it with an empty byte array:
file.bytes = new byte[0]
Passing an empty list also works, impressively.
file.bytes = []
Presumably, you want simply to overwrite the file with new content. To do that:
def content = ...
new File("test.txt").withWriter { writer ->
writer.write(content)
}
Note that File.withWriter will do all the usual housekeeping re: open/close file.
I am trying to add changes data in a csv file:
This is the sample data:
DATE status code value value2
"2016-01-26","Subscription All","119432660","1315529431362550","0.0080099833517888"
"2016-01-26","Subscription All","119432664","5836995058433524","0.033825584764444"
"2016-01-26","Subscription All","119432664","8287300074499777","0.076913377834744"
"2016-01-26","Subscription All","119432664","14870697739968326","0.0074188355187426"
My code used to format the data:
CSVReader reader = new CSVReader(new FileReader(new File(fileToChange)), CSVParser.DEFAULT_SEPARATOR, CSVParser.NULL_CHARACTER, CSVParser.NULL_CHARACTER, 1)
info "Read all rows at once"
List<String[]> allRows = reader.readAll();
CSVWriter writer = new CSVWriter(new FileWriter(fileToChange), CSVWriter.DEFAULT_SEPARATOR, CSVWriter.NO_QUOTE_CHARACTER)
writer.writeAll(allRows)
writer.close()
The output i get is this, with extra quote added instead of removing it.
""2016-01-26"",""Subscription All"",""119432660"",""1315529431362550"",""0.0080099833517888""
""2016-01-26"",""Subscription All"",""119432664"",""5836995058433524"",""0.033825584764444""
""2016-01-26"",""Subscription All"",""119432664"",""8287300074499777"",""0.076913377834744""
""2016-01-26"",""Subscription All"",""119432664"",""14870697739968326"",""0.0074188355187426""
I want to remove the quotes.
Please can someone help.
Also, is it possible to change the date format to yyyymmdd instead of yyyy-mm-dd?
allRows.each { String[] theLine ->
String newDate = theLine[0].replaceAll('-', '')
String newline = theLine.eachWithIndex { String s, int i -> return i > 0 ? s : newDate}
writer.writeLine(newline)
}
Thanks
When you instantiated your CSVReader you told it to treat no characters as quotes, therefore it read the existing quotes as data and did not remove them.
When you told CSVWriter not to add any quotes it honored your request. However, the input data contained quote characters, and the convention for including quotes inside a string in CSV is to double the quotes. Thus the
string value
ABC"DEF
gets coded in CSV as
"ABC""DEF"
So the result you see is the combination of not removing the quotes on input (you told it not to) and then doubling the quotes on output.
To solve this change the input option from NULL_CHARACTER to DEFAULT_QUOTE_CHARACTER. However be aware that if any of your data actually contains embedded quotes or commas the resulting output will not be valid CSV.
Also I think this might be a valid bug report against OpenCSV. I believe that OpenCSV needs to inform you if it is about to generate invalid CSV when you told it to omit quotes, probably via a runtime exception. Although I suppose they might argue that you chose to work without a net and should accept whatever you get. Personally I go for the "principle of least surprise", which IMHO would be not to double quotes when the output is unquoted.
Because quotation in your CSVReader is set to CSVParser.NULL_CHARACTER " is treated as normal character which is part of read token. This causes your array to contain data in form:
["2016-01-26", "Subscription All", "119432660", "1315529431362550", "0.0080099833517888"]
rather than:
[2016-01-26, Subscription All, 119432660, 1315529431362550, 0.0080099833517888]
So try changing option from CSVParser.NULL_CHARACTER to either
'"'
CSVParser.DEFAULT_QUOTE_CHARACTER (it also stores '"').
CsvToBean csvToBean = new CsvToBeanBuilder(new StringReader(csv))
.withMappingStrategy(strategy)
.withIgnoreLeadingWhiteSpace(true)
.withSeparator(',')
.withIgnoreEmptyLine(true)
.withQuoteChar('\'')
.withQuoteChar('"')
.build();
I want to write a function that loads a text file and plots its content with time. I have 20 text files so I want to be able to choose from them.
My current not working code:
TextFile is a generic variable
text123.txt is the actual name of one of the files i want to load
function []= PlotText(TextFile)
text(1,:)=load('text123.txt') ;
t=0:10;
plot(t,text)
end
I appreciate any help!!
use importdata instead of load with appropriate delimiter. I assume you used Tab.
filename = 'num.txt';
delimiterIn = '\t';
text = importdata(filename,delimiterIn)
t=1:10;
plot(t,text);
Firstly, you can also use dlmread if your file contains only numeric data separated by the same symbol (called a delimiter) such as a comma (,), semicolon (;), space ( ), or tab ( ). This would look like:
function []= PlotText(TextFile)
text(1,:)=dlmread('text123.txt');
t=0:10;
plot(t,text)
end
Keep in mind that your code is written in a way that expects the contents of text123.txt to have 11 values in a single row. Also, if you are using multiple files, then I suggest having the file name be another input to the function:
function []= PlotText(TextFile,filename)
text(1,:)=load(filename) ;
t=0:10;
plot(t,text)
end
I would like to read an excel file (xlsread) but I don't want to put manually the string every time but instead I want to xlsread the name of the file that is contained in an array.
For example, my array B is:
B =
'john.xlsx'
'mais.xlsx'
'car.xlsx'
Then I would like to read the excel WITH THE NAME that is inside the first element, that means: "john.xlsx"
How can I do this?
data = xlsread(B{1});
Or, if you want to read all of them:
for i=1:length(B)
data(i).nums = xlsread(B{i});
end
Assuming, of course, your B is a cell array. If it's not, it can't exist the way you described it. If all strings have the same length (then it would be possible) or padding with spaces, you can split the char array into a cell array using
B = mat2cell(B,ones(size(B,1),1),size(B,2));
Strings of different lengths would have to be inside a cell array, which you can access elements via the curly brackets {}. So, you can call xlsread on the first element this way:
names{1} = 'john.xlsx';
names{2} = 'mais.xlsx';
names{3} = 'car.xlsx';
num = xlsread(names{1});
I don't know if Matlab can do this, but I want to store some strings in a 4×3 matrix, each element in the matrix is a string.
test_string_01 test_string_02 test_string_03
test_string_04 test_string_05 test_string_06
test_string_07 test_string_08 test_string_09
test_string_10 test_string_11 test_string_12
Then, I want to write this matrix into a plain text file, either comma or space delimited.
test_string_01,test_string_02,test_string_03
test_string_04,test_string_05,test_string_06
test_string_07,test_string_08,test_string_09
test_string_10,test_string_11,test_string_12
Seems like matrix data type is not capable of storing strings. I looked at cell. I tried to use dlmwrite() or csvwrite(), but both of them only accept matrices. I also tried cell2mat() first, but in that way all letters in the strings are comma seperated, like
t,e,s,t,_,s,t,r,i,n,g,_,0,1,t,e,s,t,_,s,t,r,i,n,g,_,0,2,t,e,s,t,_,s,t,r,i,n,g,_,0,3
So is there any way to achieve this?
It is possible to shorten yuk's solution a bit.
strings = {
'test_string_01','test_string_02','test_string_03'
'test_string_04','test_string_05','test_string_06'
'test_string_07','test_string_08','test_string_09'
'test_string_10','test_string_11','test_string_12'};
fid = fopen('output.txt','w');
fmtString = [repmat('%s\t',1,size(strings,2)-1),'%s\n'];
fprintf(fid,fmtString,strings{:});
fclose(fid);
Cell array is the way to store strings.
I agree it's a pain to save strings into a text file, but you can do it with this code:
strings = {
'test_string_01','test_string_02','test_string_03'
'test_string_04','test_string_05','test_string_06'
'test_string_07','test_string_08','test_string_09'
'test_string_10','test_string_11','test_string_12'};
fid = fopen('output.txt','w');
for row = 1:size(strings,1)
fprintf(fid, repmat('%s\t',1,size(strings,2)-1), strings{row,1:end-1});
fprintf(fid, '%s\n', strings{row,end});
end
fclose(fid);
Substitute \t with , to get csv file.
You can also store cell array of strings into Excel file with XLSWRITE (requires COM interface, so it's on Windows only):
xlswrite('output.xls',strings)
In most cases you can use the delimiter ' ' and get Matlab to save a string into file with dlmwrite.
For example,
output=('my_first_String');
dlmwrite('myfile.txt',output,'delimiter','')
will save a file named myfile.txt containing my_first_String.