Develop Reference

Get every char that's bigger than 'G'

Well I have an array which called names
string[] names = new string[] { "Brad", "Ava", "Tom", "Cooper"};
Now I want to get every char of a name which is greater than 'g'. With greater I mean every char after 'g' so h,i,j,k,l ...
This is what I already got
names.Select(x => x.ToCharArray()).ToString().ToUpper().OrderBy(x => x);
Expected result:
R
V
MOT
OOPR

Make names uppercase and filter by checking if characters are bigger than character 'G':
string[] result = names.Select(s => string.Concat(s.ToUpper()
.OrderBy(ch => ch)
.Where(ch => ch > 'G')))
.ToArray();

string[] names = new string[] { "Brad", "Ava", "Tom", "Cooper" };
char g = 'G';
foreach (var name in names)
{
foreach (var c in name.ToUpper())
if ((int)c > (int)g)
Console.Write(c);
Console.WriteLine();
}

Split String to array and Sort Array

I am trying to sort a string split by comma. But it is not behaving as expected
var classes = "10,7,8,9";
Console.Write(string.Join(",", classes.Split(',').OrderBy(x => x)));
Console.ReadKey();
and output is
10,7,8,9
But I want the expected output to be like:
7,8,9,10
Classes can have a section along with them. like 7a,7b
and I want to achieve it on one line of code.

You can use Regex like this
var classes = "10,7,8,9";
Regex number = new Regex(#"^\d+");
Console.Write(string.Join(",", classes.Split(',').OrderBy(x => Convert.ToInt32(number.Match(x).Value)).ThenBy(x => number.Replace(x, ""))));
Console.ReadKey();

CODE:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;
using System.Collections;
namespace Rextester
{
public class Program
{
public static void Main(string[] args)
{
var l = new List<string> { "1D", "25B", "30A", "9C" };
l.Sort((b, a) =>
{
var x = int.Parse(Regex.Replace(a, "[^0-9]", ""));
var y = int.Parse(Regex.Replace(b, "[^0-9]", ""));
if (x != y) return y - x;
return -1 * string.Compare(a, b);
});
foreach (var item in l) Console.WriteLine(item);
}
}
}
OUTPUT:
1D
9C
25B
30A
ONLINE COMPILE:
http://rextester.com/CKKQK66159

Use the following using-directive:
using System.Text.RegularExpressions;
And try the following:
var input = "7,7a,8,9a,9c,9d,10";
var sorted = from sp in input.Split(',')
let reg = Regex.Match(sp, #"(?<num>[0-9]+)(?<char>[a-z]*)", RegexOptions.IgnoreCase | RegexOptions.Compiled)
let number = int.Parse(reg.Groups["num"].ToString())
orderby reg.Groups["char"].ToString() ascending // sort first by letter
orderby number ascending // then by number
select sp;
var result = string.Join(",", sorted);
Console.WriteLine(result);
//output (tested): 7,7a,8,9a,9c,9d,10
It uses regex to determine the numeric and alphabetic part of the input string.
The regex pattern uses named groups, which are noted as follows: (?<group_name> regex_expr ).
The time complexity of the code above is O(n log(n)), in case you are worried about big collections of numbers.
More information about named Regex groups.
More information about LINQ.
... and about the orderby-clause.

All on one line, also supports '4a' etc.
edit: On testing this, a string such as 1,2,111,3 would display as 111,1,2,3, so may not quite be what you're looking for.
string str = "1,2,3,4a,4b,5,6,4c";
str.Split(',').OrderBy(x => x).ToList().ForEach(x=> Console.WriteLine(x));
Console.ReadKey();

Here is my implementation:
IEnumerable<Tuple<string, string[]>> splittedItems =
items.Select(i => new Tuple<string, string[]>(i, Regex.Split(i, "([0-9]+)")));
List<string> orderedItems = splittedItems.OrderBy(t => Convert.ToInt16(t.Item2[1]))
.ThenBy(t => t.Item2.Length > 1 ? t.Item2[2] : "1")
.Select(t => t.Item1).ToList();
Split the input to a number and non numeric characters
Store the splitted strings with their parent string
Order by number
Then order by non numeric characters
Take the parent string again after sorting
The result is like required: { "10", "7", "8b", "8a", "9" } is sorted to { "7", "8a", "8b", "9", "10" }

You are sorting strings (alphabetically), so yes, "10" comes before "7".
My solution converts "10,7b,8,7a,9b" to "7a,7b,8,9b,10" (first sort by the integer prefix, then by the substring itself).
Auxiliary method to parse the prefix of a string:
private static int IntPrefix(string s)
=> s
.TakeWhile(ch => ch >= '0' && ch <= '9')
.Aggregate(0, (a, c) => 10 * a + (c - '0'));
Sorting the substrings by the integer prefix then by the string itself:
classes.Split(',') // string[]
.Select(s => new { s, i = IntPrefix(s) }) // IEnumerable<{ s: string, i: int }>
.OrderBy(si => si.i) // IEnumerable<{ s: string, i: int }>
.ThenBy(si => si.s) // IEnumerable<{ s: string, i: int }>
.Select(si => si.s) // IEnumerable<string>
One liner (with string.Join):
var result = string.Join(",", classes.Split(',').Select(s => new {s, i = IntPrefix(s)}).OrderBy(si => si.i).ThenBy(si => si.s).Select(si => si.s));

How to find maximum number of repeated string in a string in a list of string in c#

If we have a list of strings, then how we can find the list of strings that have the maximum number of repeated symbol by using LINQ.
List <string> mylist=new List <string>();
mylist.Add("%1");
mylist.Add("%136%250%3"); //s0
mylist.Add("%1%5%20%1%10%50%8%3"); // s1
mylist.Add("%4%255%20%1%14%50%8%4"); // s2
string symbol="%";
List <string> List_has_MAX_num_of_symbol= mylist.OrderByDescending(s => s.Length ==max_num_of(symbol)).ToList();
//the result should be a list of s1 + s2 since they have **8** repeated '%'
I tried
var longest = mylist.Where(s => s.Length == mylist.Max(m => m.Length)) ;
this gives me only one string not both

Here's a very simple solution, but not exactly efficient. Every element has the Count operation performed twice...
List<string> mylist = new List<string>();
mylist.Add("%1");
mylist.Add("%136%250%3"); //s0
mylist.Add("%1%5%20%1%10%50%8%3"); // s1
mylist.Add("%4%255%20%1%14%50%8%4"); // s2
char symbol = '%';
var maxRepeat = mylist.Max(item => item.Count(c => c == symbol));
var longest = mylist.Where(item => item.Count(c => c == symbol) == maxRepeat);
It will return 2 strings:
"%1%5%20%1%10%50%8%3"
"%4%255%20%1%14%50%8%4"

Here is an implementation that depends upon SortedDictionary<,> to get what you're after.
var mylist = new List<string> {"%1", "%136%250%3", "%1%5%20%1%10%50%8%3", "%4%255%20%1%14%50%8%4"};
var mappedValues = new SortedDictionary<int, IList<string>>();
mylist.ForEach(str =>
{
var count = str.Count(c => c == '%');
if (mappedValues.ContainsKey(count))
{
mappedValues[count].Add(str);
}
else
{
mappedValues[count] = new List<string> { str };
}
});
// output to validate output
foreach (var str in mappedValues.Last().Value)
{
Console.WriteLine(str);
}
Here's one using LINQ that gets the result you're after.
var result = (from str in mylist
group str by str.Count(c => c == '%')
into g
let max = (from gKey in g select g.Key).Max()
select new
{
Count = max,
List = (from str2 in g select str2)
}).LastOrDefault();

OK, here's my answer:
char symbol = '%';
var recs = mylist.Select(s => new { Str = s, Count = s.Count(c => c == symbol) });
var maxCount = recs.Max(x => x.Count);
var longest = recs.Where(x => x.Count == maxCount).Select(x => x.Str).ToList();
It is complicated because it has three lines (the char symbol = '%'; line excluded), but it counts each string only once. EZI's answer has only two lines, but it is complicated because it counts each string twice. If you really want a one-liner, here it is:
var longest = mylist.Where(x => x.Count(c => c == symbol) == mylist.Max(y => y.Count(c => c == symbol))).ToList();
but it counts each string many times. You can choose whatever complexity you want.

We can't assume that the % is always going to be the most repeated character in your list. First, we have to determine what character appears the most in an individual string for each string.
Once we have the character and it maximum occurrence, we can apply Linq to the List<string> and grab the strings that contain the character equal to its max occurrence.
using System;
using System.Collections.Generic;
using System.Linq;
public class Program
{
public static void Main()
{
List <string> mylist=new List <string>();
mylist.Add("%1");
mylist.Add("%136%250%3");
mylist.Add("%1%5%20%1%10%50%8%3");
mylist.Add("%4%255%20%1%14%50%8%4");
// Determine what character appears most in a single string in the list
char maxCharacter = ' ';
int maxCount = 0;
foreach (string item in mylist)
{
// Get the max occurrence of each character
int max = item.Max(m => item.Count(c => c == m));
if (max > maxCount)
{
maxCount = max;
// Store the character whose occurrence equals the max
maxCharacter = item.Select(c => c).Where(c => item.Count(i => i == c) == max).First();
}
}
// Print the strings containing the max character
mylist.Where(item => item.Count(c => c == maxCharacter) == maxCount)
.ToList().ForEach(Console.WriteLine);
}
}
Results:
%1%5%20%1%10%50%8%3
%4%255%20%1%14%50%8%4
Fiddle Demo

var newList = myList.maxBy(x=>x.Count(y=>y.Equals('%'))).ToList();
This should work. Please correct syntax if wrong anywhere and update here too if it works for you.

Given collection of strings, count number of times each word appears in List<T>

Input 1: List<string>, e.g:
"hello", "world", "stack", "overflow".
Input 2: List<Foo> (two properties, string a, string b), e.g:
Foo 1:
a: "Hello there!"
b: string.Empty
Foo 2:
a: "I love Stack Overflow"
b: "It's the best site ever!"
So i want to end up with a Dictionary<string,int>. The word, and the number of times it appears in the List<Foo>, either in the a or the b field.
Current first-pass/top of my head code, which is far too slow:
var occurences = new Dictionary<string, int>();
foreach (var word in uniqueWords /* input1 */)
{
var aOccurances = foos.Count(x => !string.IsNullOrEmpty(x.a) && x.a.Contains(word));
var bOccurances = foos.Count(x => !string.IsNullOrEmpty(x.b) && x.b.Contains(word));
occurences.Add(word, aOccurances + bOccurances);
}

Roughly:
Build a dictionary (occurrences) from the first input, optionally with a case-insensitive comparer.
For each Foo in the second input, use RegEx to split a and b into words.
For each word, check if the key exists in occurrences. If it exists, increment and update the value in the dictionary.

You could try concating the two strings a + b. Then doing a regex to pull out all the words into a collection. Then finally indexing that using a group by query.
For example
void Main()
{
var a = "Hello there!";
var b = "It's the best site ever!";
var ab = a + " " + b;
var matches = Regex.Matches(ab, "[A-Za-z]+");
var occurences = from x in matches.OfType<System.Text.RegularExpressions.Match>()
let word = x.Value.ToLowerInvariant()
group word by word into g
select new { Word = g.Key, Count = g.Count() };
var result = occurences.ToDictionary(x => x.Word, x => x.Count);
Console.WriteLine(result);
}
Example with some changes suggested...
Edit. Just reread the requirement....kinda strange but hey...
void Main()
{
var counts = GetCount(new [] {
"Hello there!",
"It's the best site ever!"
});
Console.WriteLine(counts);
}
public IDictionary<string, int> GetCount(IEnumerable<Foo> inputs)
{
var allWords = from input in inputs
let matchesA = Regex.Matches(input.A, "[A-Za-z']+").OfType<System.Text.RegularExpressions.Match>()
let matchesB = Regex.Matches(input.B, "[A-Za-z']+").OfType<System.Text.RegularExpressions.Match>()
from x in matchesA.Concat(matchesB)
select x.Value;
var occurences = allWords.GroupBy(x => x, (x, y) => new{Key = x, Count = y.Count()}, StringComparer.OrdinalIgnoreCase);
var result = occurences.ToDictionary(x => x.Key, x => x.Count, StringComparer.OrdinalIgnoreCase);
return result;
}

C# Combining lines

Hey everybody, this is what I have going on. I have two text files. Umm lets call one A.txt and B.txt.
A.txt is a config file that contains a bunch of folder names, only 1 listing per folder.
B.txt is a directory listing that contains folders names and sizes. But B contains a bunch of listing not just 1 entry.
What I need is if B, contains A. Take all lines in B that contain A and write it out as A|B|B|B ect....
So example:
A.txt:
Apple
Orange
Pear
XBSj
HEROE
B.txt:
Apple|3123123
Apple|3434
Orange|99999999
Orange|1234544
Pear|11
Pear|12
XBSJ|43949
XBSJ|43933
Result.txt:
Apple|3123123|3434
Orange|99999999|1234544
Pear|11|12
XBSJ|43949|43933
This is what I had but it's not really doing what I needed.
string[] combineconfig = File.ReadAllLines(#"C:\a.txt");
foreach (string ccline in combineconfig)
{
string[] readlines = File.ReadAllLines(#"C:\b.txt");
if (readlines.Contains(ccline))
{
foreach (string rdlines in readlines)
{
string[] pslines = rdlines.Split('|');
File.AppendAllText(#"C:\result.txt", ccline + '|' + pslines[0]);
}
}
I know realize it's not going to find the first "if" because it reads the entire line and cant find it. But i still believe my output file will not contain what I need.

Assuming you're using .NET 3.5 (so can use LINQ), try this:
string[] configLines = File.ReadAllLines("a.txt");
var dataLines = from line in File.ReadAllLines("b.txt")
let split = line.Split('|')
select new { Key = split[0], Value = split[1] };
var lookup = dataLines.ToLookup(x => x.Key, x => x.Value);
using (TextWriter writer = File.CreateText("result.txt"))
{
foreach (string key in configLines)
{
string[] values = lookup[key].ToArray();
if (values.Length > 0)
{
writer.WriteLine("{0}|{1}", key, string.Join("|", values));
}
}
}

var a = new HashSet<string>(File.ReadAllLines(#"a.txt")
.SelectMany(line => line.Split(' ')),
StringComparer.CurrentCultureIgnoreCase);
var c = File.ReadAllLines(#"b.txt")
.Select(line => line.Split('|'))
.GroupBy(item => item[0], item => item[1])
.Where(group => a.Contains(group.Key))
.Select(group => group.Key + "|" + string.Join("|", group.ToArray()))
.ToArray();
File.WriteAllLines("result.txt", c);
Output:
Apple|3123123|3434
Orange|99999999|1234544
Pear|11|12
XBSJ|43949|43933

A short one :
var a = File.ReadAllLines("A.txt");
var b = File.ReadAllLines("B.txt");
var query =
from bline in b
let parts = bline.Split('|')
group parts[1] by parts[0] into bg
join aline in a on bg.Key equals aline
select aline + "|" + string.Join("|", bg.ToArray());
File.WriteAllLines("result.txt", query.ToArray());

This should work:
using System;
using System.Linq;
using System.IO;
using System.Globalization;
namespace SO2593168
{
class Program
{
static void Main(string[] args)
{
var a = File.ReadAllLines("A.txt");
var b =
(from line in File.ReadAllLines("B.txt")
let parts = line.Split('|')
select new { key = parts[0], value = parts[1] });
var comparer = StringComparer.Create(CultureInfo.InvariantCulture, true);
var result =
from key in a
from keyvalue in b
where comparer.Compare(keyvalue.key, key) == 0
group keyvalue.value by keyvalue.key into g
select new { g.Key, values = String.Join("|", g.ToArray()) };
foreach (var entry in result)
Console.Out.WriteLine(entry.Key + "|" + entry.values);
}
}
}
This produces:
Apple|3123123|3434
Orange|99999999|1234544
Pear|11|12
XBSJ|43949|43933
Code here.