I have a text file named my_date.txt containing following data:
1 Adam
2 Steve
3 Lisa
4 Josh
.....
The text file may be very long. I am trying to load this data contained in this text file into an array in C# so that I could do an operation. In sas I just use input. In VBA I just refer the cells, assuming I make it in excel. But here with C#, I have no idea at all.
#1 Simple For
You can use File.ReadAllLines to put the lines of a text file into a string array.
string[] names = File.ReadAllLines("C:\\my_date.txt");
And then parse the data to remove the 1, 2, 3, etc before the names
for (int i = 0; i < names.Length; i++)
{
names[i] = names[i].Split()[1];
}
#2 LINQ
Using the simple for loop will work fine, but alternatively you can use LINQ:
string[] names = File.ReadAllLines("C:\\my_date.txt")
.Select(str => str.Split()).Select(name => name[1]).ToArray();
In the event that you don't need a number prefix, you can simply use the ReadAllLines method without the Split()
In C# you can do that using File.ReadLines method and LINQ:
var values = File
.ReadLines("filePath") // 1
.Select(x => x.Split()) // 2
.Select(x => new { Id = x[0], Name = string.Join(" ", x.Skip(1) }) // 3
.ToArray(); // 4
Read all lines from the file
Split each line by white-space
Create an anonymous object for each line that contains two property Id (number), and the Name, I used string.Join because your names might contain white-spaces.You can use a custom class instead of anonymous type that would be more appropriate.
Convert the result into an array.
Related
string[] splittedText = File.ReadAllLines(#"file.txt");//.Split(',');
foreach (string data in splittedText)
{
}
I want to read through a file in c# which returns array of string type. Then, I will be iterating over the array to fetch my desired data.
If you want to read a CSV file, you should use a CVS parser. Values in the CSV file are separated using command and in some cases, the value in the CSV file can also contain a comma. In that case, the column values are wrapped in double-quotes. And this solution will not handle that scenario.
var splittedText = File.ReadAllText("E:\\Test.txt").Split(',');
foreach (string data in splittedText)
{
Console.WriteLine(data.Trim());
}
Hint - Reading file line by line or Reading whole file content depends on your use case. May be below code snippet give some idea on how to split the content.
Please try.
var inputtext = File.ReadAllText(#"inpufile.txt");
inputtext.Replace("\n", "")
.Split(',',
StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries)
.ToList().ForEach(t =>
{
System.Console.WriteLine(t);
//Other manupulations
});
if you want to split based on multiple characters , pass a character array to the split().
new char[] { ',', ':' };
Thank you.
You need change File.ReadAllLines to File.ReadAllText(path) then you can split method.
I need read a text file (10mb) and convert to .csv. See below portion of code:
string DirPathForm = System.IO.Path.GetDirectoryName(System.Reflection.Assembly.GetEntryAssembly().Location);'
string[] lines = File.ReadAllLines(DirPathForm + #"\file.txt");
Some portion of the text file have a pattern. So, used as below:
string[] lines1 = lines.Select(x => x.Replace("abc[", "ab,")).ToArray();
Array.Clear(lines, 0, lines.Length);
lines = lines1.Select(x => x.Replace("] CDE ", ",")).ToArray();
Some portion does not have a pattern to use directly Replace. The question is how remove the characters, numbers and whitespaces in this portion. Please see below?
string[] lines = {
"a] 773 b",
"e] 1597 t",
"z] 0 c"
};
to get the result below:
string[] result = {
"a,b",
"e,t",
"z,c"
};
obs: the items removed need be replaced by ",".
First of all, you should not use ReadAllLines since it is a huge file operation. It will load all the data into RAM and it is not correct. Instead, read the lines one by one in a loop.
Secondly, you can definitely use regex to replace data from the first condition to the second one.
I need to find distinct values of partial filenames in an array of filenames. I'd like to do it in one line.
So, I have something like that as a filenames:
string[] filenames = {"aaa_ab12345.txt", "bbb_ab12345.txt", "aaa_ac12345.txt", "bbb_ac12345"}
and I need to find distinct values for ab12345 part of it.
So I currently have something like that:
string[] filenames_partial_distinct = Array.ConvertAll(
filenames,
file => System.IO.Path.GetFileNameWithoutExtension(file)
.Split({"_","."}, StringSplitOptions.RemoveEmptyEntries)[1]
)
.Distinct()
.ToArray();
Now, I'm getting filenames that are of form of aaa_bbb_ab12345.txt. So, instead of referring to the second part of the filename, I need to refer to the second to the last.
So, how do I refer to an arbitrary element based on length of array in one line, if it's a result of Split method? Something along lines of:
Array.ConvertAll(filenames, file=>file.Split(separator)[this.Length-2]).Distinct().ToArray();
In other words, if a string method results in an array of strings, how do I immediately select element based on the length of array:
String.Split()[third from end, fifth from end, etc.];
If you use GetFileNameWithoutExtension there will be no extension and therefore splitting by '_' will do it. Then you can take the last part with .Last().
string[] filenames_partial_distinct = Array.ConvertAll(
filenames,
file => Path.GetFileNameWithoutExtension(file).Split('_').Last()
)
.Distinct()
.ToArray();
With the input
string[] filenames = { "aaa_ab12345.txt", "bbb_ab12345.txt",
"aaa_ac12345.txt", "bbb_ac12345", "aaa_bbb_ab12345.txt" };
You get the result
{ "ab12345", "ac12345" }
The StringSplitOptions.RemoveEmptyEntries is only required if there are filenames ending with _ (before the extension).
Seems you're looking for something like this:
string[] arr = filenames.Select(n => n.Substring(n.IndexOf("_") + 1, 7)).Distinct().ToArray();
I usually defer problems like this to regex. They are very powerful. This approach also gives you the opportunity to detect unexpected cases and handle them appropriately.
Here is a crude example, assuming I understood your requirements:
using System;
using System.Linq;
using System.Text.RegularExpressions;
public class Program
{
public static void Main()
{
string MyMatcher(string filename)
{
// this pattern may need work depending on what you need - it says
// extract that pattern between the "()" which is 2 characters and
// 4 digits, exactly; and can be found in `Groups[1]`.
Regex r = new Regex(#".*_(\w{2}\d{4}).*", RegexOptions.IgnoreCase);
Match m = r.Match(filename);
return m.Success
? m.Groups[1].ToString()
: null; // what should happen here?
}
string[] filenames =
{
"aaa_ab12345.txt",
"bbb_ab12345.txt",
"aaa_ac12345.txt",
"bbb_ac12345",
"aaa_bbb_ab12345.txt",
"ae12345.txt" // MyMatcher() return null for this - what should you do if this happens?
};
var results = filenames
.Select(MyMatcher)
.Distinct();
foreach (var result in results)
{
Console.WriteLine(result);
}
}
}
Gives:
ab1234
ac1234
This can be refined further, such as pre-compiled regex patterns, encapsulation in a class, etc.
I have one array with names
string[] arr = { "John", "karl", "Ralf", "Florian" };
And, I have one array of lines of one file
var lines = File.ReadAllLines("test.txt");
And, inside of that column, I have some names, random names, in a specific position of the line, for example, column 10 to column 20.
How I do this now, I have an encadead loop, where I search line by line from specific name of index of first loop
for(int i=0;i<arr.Lenght;i++)
for(int j=0;j<lines.Lenght;j++)
if(lines[j].substring(10,10).trim() == arr[i].Trim())
list.Add(lines[j])
That is a very poor way, i know :(
But, I want to know, if is possible to do this using Linq, if yes, how it's possible ?
I think this should do the job
list = lines.Where(x=>arr.Contains(x.Substring(10,10).Trim()));
it will create a list from lines where line substring (10,20) is in arr
Try this:
var result = lines
.Where(line => arr.Contains(line.Substring(10, 10).Trim()))
.ToList();
Trim on arr elements is not needed - they're already trimmed. ToList can be skipped to get a lazy IEnumerable<string> or replaced with ToArray if you prefer.
LINQ, in query comprehension syntax:
var result = from line in lines
let trimmed = line.Substring(10,10).Trim()
where arr.Contains(trimmed)
select line;
NOTE: result will contain an enumeration over non-trimmed lines, which is what the OP's code originally does.
Having a bit of trouble with converting a comma separated text file to a generic list. I have a class (called "Customers") defined with the following attributes:
Name (string)
City (string)
Balance (double)
CardNumber (int)
The values will be stored in a text file in this format: Name,City, Balance, CarNumber e.g. John,Memphis,10,200789. There will be multiple lines of this. What I want to do is have each line be placed in a list item when the user clicks a button.
I've worked out I can break each line up using the .Split() method, but have no idea how to make the correct value go into the correct attribute of the list. (Please note: I know how to use get/set properties, and I am not allowed to use LINQ to solve the problem).
Any help appreciated, as I am only learning and have been working on this for a for while with no luck. Thanks
EDIT:
Sorry, it appears I'm not making myself clear. I know how to use .add.
If I have two lines in the text file:
A,B,1,2 and
C,D,3,4
What I don't know how to do is make the name "field" in the list item in position 0 equal "A", and the name "field" in the item in position 1 equal "C" and so on.
Sorry for the poor use of terminology, I'm only learning. Hope you understand what I'm asking (I'm sure it's really easy to do once you know)
The result of string.Split will give you an array of strings:
string[] lineValues = line.Split(',');
You can access values in an array by index:
string name = lineValues[0];
string city = lineValues[1];
You can convert strings to double or int using their respective Parse methods:
double balance = double.Parse(lineValues[2]);
int cardNumber = int.Parse(lineValues[3]);
You can instantiate the class and assign to it very simply:
Customer customerForCurrentLine = new Customer()
{
Name = name,
City = city,
Balance = balance,
CardNumber = cardNumber,
};
Simply loop over the lines, instantiate a Customer for that line, and add it to a variable you've created of the type List<Customer>
If you want your program to be bulletproof, you're going to have to do a lot of checking to skip over lines that don't have enough values, or that would fail to parse to the correct number type. For example, check lineValues.Length == 4 and use int.TryParse(...) and double.TryParse(...).
Read a file and split its text based on newline character. Then for total line count run a loop that will split based on comma and create a new object and insert values in its properties and add that object to a list.
This way
List<Customers> lst = new List<Customers>();
string[] str = System.IO.File.ReadAllText(#"C:\CutomersFile.txt")
.Split(new string[] { Environment.NewLine },
StringSplitOptions.None);
for (int i = 0; i < str.Length; i++)
{
string[] s = str[i].Split(',');
Customers c = new Customers();
c.Name = s[0];
c.City = s[1];
c.Balance = Convert.ToDouble(s[2]);
c.CardNumber = Convert.ToInt32(s[3]);
lst.Add(c);
}
BTW class name should be Customer and not Customers
Split() generates an array of strings in the order they appeared in the source string. Thus, if your name field is the first column in the CSV file, it will always be the first index in the array.
someCustomer.Name = splitResult[0];
And so on. You'll also need to investigate String.TryParse for your class's numerically typed properties.