I am having an issue when reading from a file using comma split. I can read the file like this:
CSVReader reader = new CSVReader(new FileReader(FileName), '|' , '"' , 0);
Then when I want to get the individual values, I can read them like this:
String[] record = rowString.split(",");
The issue of course is that comma is not the most reliable way to read a file. Is there any way to split the string by pipe delimited like this?:
String[] record = rowString.split("\\|");
This is how I am reading the lines, it may possibly be in this code where I need to make such adjustment?
for(String[] row : allRows){
String rowString = Arrays.toString(row).toString();
String[] record = rowString.split(",");
}
Thank you.
I don't know if this answer the question but in my case this solve the problem:
val reader: Reader = Files.newBufferedReader(path)
val csvToBean = CsvToBeanBuilder<MyCsvSchema>(reader)
.withType(MyCsvSchema::class.java)
.withSeparator('|')
.withIgnoreLeadingWhiteSpace(true)
.build()
val list = csvToBean.parse()
This is a Kotlin code
Related
I am using scanner to delimiting tokens by ";". I need when strings are quoted,
that ; would be ignored by scanner in quotes "". Also need delimiting by "".
0 1 2
A ProjectID Name Describtion Summary
B ID-322;"oba stb; iba logo ""T"" ";dg-eiiod
C ID-349;Sttring;dg-enc05
D ID-888;Data;dg-enc05
As you see in string "oba stb; iba logo""T"" ";is my delimiter.
I need to make scanner ignore it, now it would split it as"oba stb"iba logo ""T"" "` which I don't want.
now I have
scanner.useDelimiter(";|\t");
Don't use Scanner for parsing CSV files, use a CSV parser.
Almost all Java-based CSV parsers allow you to use delimiters other that commas.
E.g. with Apache Commons CSV (just to pick a random one):
CSVFormat format = CSVFormat.RFC4180.withDelimiter(';');
Charset charset = Charset.defaultCharset(); // or StandardCharsets.UTF_8
try (CSVParser parser = CSVParser.parse(file, charset, format)) {
for (CSVRecord record : parser) {
String projectID = record.get("ProjectID");
String name = record.get("Name");
String description = record.get("Describtion");
...
}
}
I need to write a program for a project at university which should cut some specific parts out of a given CSV File. I've started already but I don't know how to keep only the content (sentence and vote values) or min. to remove the date part.
PARENT,"Lorem ipsum...","3","0","Town","09:17, 29/11/2016"
REPLY,"Loren ipsum...”,"2","0","Town","09:18, 29/11/2016"
After the program ran I want to have it like this:
Lorem ipsum... (String) 3 (int) 0 (int)
Loren ipsum... (String) 2 (int) 0 (int)
I have no problem with writing a parser (read in, remove separators) but I don't know how realize this thing.
You can create your own data structure that contains a string, and two integers and then do the following while reading from the csv file. Only include the stuff you want from the csv based on the column number which is the index of the String array returned by the split() method.
Scanner reader = new Scanner(new File("path to your CSV File"));
ArrayList<DataStructure> csvData = new ArrayList<>();
while(reader.hasNextLine())
{
String[] csvLine = reader.nextLine().split(",");
DataStructure data = new DataStructure(
csvLine[1],
Integer.parseInt(csvLine[2]),
Integer.parseInt(csvLine[3]));
csvData.add(data);
}
I have been looking for the past 2 hours for a solution to my problem in vain. I'am trying to read a CSV File using Apache commons ,I am able to read the whole file but my problem is how to extract only the header of the CSV in an array?
I looked everywhere and even the solution above didn't work.
For anyone else with this issue, this does.
Iterable<CSVRecord> records;
Reader in = new FileReader(fileLocation);
records = CSVFormat.EXCEL.withHeader().withSkipHeaderRecord(false).parse(in);
Set<String> headers = records.iterator().next().toMap().keySet();
Note that your use of .next() has consumed one row of the CSV.
By default, first record read by CSVParser will always be a header record, e.g. in the below example:
CSVFormat csvFileFormat = CSVFormat.DEFAULT.withHeader(FILE_HEADER_MAPPING);
FileReader fileReader = new FileReader("file");
CSVParser csvFileParser = new CSVParser(fileReader, csvFileFormat);
List csvRecords = csvFileParser.getRecords();
csvRecords.get(0) will return the header record.
BufferedReader br = new BufferedReader(new FileReader(filename));
CSVParser parser = CSVParser.parse(br, CSVFormat.EXCEL.withFirstRecordAsHeader());
List<String> headers = parser.getHeaderNames();
This worked for me. The last line is what you need, extracts the headers found by the parser into a List of Strings.
Since Apache Commons CSV v1.9.0, the withSkipHeaderRecord() & the withFirstRecordAsHeader() methods are deprecated. A builder interface is provided. Use it thusly:
CSVFormat.DEFAULT.builder()
.setHeader()
.setSkipHeaderRecord(true)
.build();
In Kotlin:
val reader = File(path).bufferedReader()
val records = CSVFormat.DEFAULT.withFirstRecordAsHeader()
.withIgnoreHeaderCase()
.withTrim()
.parse(reader)
println(records.headerNames)
The code below works for me:
import java.io.FileReader;
import org.apache.commons.csv.*;
public static String[] headersInCSVFile (String csvFilePath) throws IOException {
//reading file
CSVFormat csvFileFormat = CSVFormat.DEFAULT;
FileReader fileReader = new FileReader(csvFilePath);
CSVParser csvFileParser = new CSVParser(fileReader, csvFileFormat);
List csvRecords = csvFileParser.getRecords();
//Obtaining first record and splitting that into an array using delimiters and removing unnecessary text
String[] headers = csvRecords.get(0).toString().split("[,'=\\]\\[]+");
String[] result = new String[headers.length - 6];
for (int i = 6; i < headers.length; i++) {
//.replaceAll("\\s", "") removes spaces
result[i - 6] = headers[i].replaceAll("\\s", "");
}
return result;
}
I have a .csv file that contains:
scenario, custom, master_data
1, ${CUSTOM}, A_1
I have a string:
a, b, c
and I want to replace 'custom' with 'a, b, c'. How can I do that and save to the existing .csv file?
Probably the easiest way is to read in one file and output to another file as you go, modifying it on a per-line basis
You could try something with tokenizers, this may not be completely correct for your output/input, but you can adapt it to your CSV file formatting
BufferedReader reader = new BufferedReader(new FileReader("input.csv"));
BufferedWriter writer = new BufferedWriter(new FileWriter("output.csv"));
String custom = "custom";
String replace = "a, b, c";
for(String line = reader.readLine(); line != null; line = reader.readLine())
{
String output = "";
StringTokenizer tokenizer = new StringTokenizer(line, ",");
for(String token = tokenizer.nextToken(); tokenizer.hasMoreTokens(); token = tokenizer.nextToken())
if(token.equals(custom)
output = "," + replace;
else
output = "," + token;
}
readInventory.close();
If this is for a one off thing, it also has the benefit of not having to research regular expressions (which are quite powerful and useful, good to know, but maybe for a later date?)
Have a look at Can you recommend a Java library for reading (and possibly writing) CSV files?
And once the values have been read, search for strings / value that start with ${ and end with }. Use Java Regular Expressions like \$\{(\w)\}. Then use some map for looking up the found key, and the related value. Java Properties would be a good candidate.
Then write a new csv file.
Since your replacement string is quite unique you can do it quickly without complicated parsing by just reading your file into a buffer, and then converting that buffer into a string. Replace all occurrences of the text you wish to replace with your target text. Then convert the string to a buffer and write that back to the file...
Pattern.quote is required because your string is a regular expression. If you don't quote it you may run into unexpected results.
Also it's generally not smart to overwrite your source file. Best is to create a new file then delete the old and rename the new to the old. Any error halfway will then not delete all your data.
final Path yourPath = Paths.get("Your path");
byte[] buff = Files.readAllBytes(yourPath);
String s = new String(buff, Charset.defaultCharset());
s = s.replaceAll(Pattern.quote("${CUSTOM}"), "a, b, c");
Files.write(yourPath, s.getBytes());
Basically, I want to parse, line by line, a Text file so that every line is in it's own array value.
E.g.
Hi There,
My Name's Aiden,
Not Really.
Array[0] = "Hi There"
Array[1] = "My Name's Aiden"
Array[2] = "Not Really"
But all the examples I have read already just confuse me and lead me to get frustrated. Maybe it's the way I approach it.
I don't know how to go about it, a point in the right direction would be most satisfying.
My suggestion is to use List<String> instead of String[] as arrays have fixed size, and that size is unknown before reading. Afterward one could make an array out of it, but to no real purpose.
For reading one has to know the encoding of the file.
Path path = Paths.get("C:/Users/Me/list.txt");
//Charset encoding = StandardCharsets.UTF_8;
Charset encoding = Charset.defaultCharset();
List<String> lines = Files.readAllLines(path, encoding);
for (String line : lines) {
...
}
for (int i = 0; i < lines.size(); ++i) {
String line = lines.get(i);
lines.set(i, "-- " + line;
}