We Keep Coding

Get certain value in the string from text file

I have this in my text file:
000000000:Carrots:$1.99:214:03/11/2015:03/11/2016:$0.99
000000001:Bananas:$1.99:872:03/11/2015:03/11/2016:$0.99
000000002:Chocolate:$2.99:083:03/11/2015:03/11/2016:$1.99
000000003:Spaghetti:$3.99:376:03/11/2015:03/11/2016:$2.99
000000004:Tomato Sauce:$1.99:437:03/11/2015:03/11/2016:$0.99
000000005:Lettuce:$0.99:279:03/11/2015:03/11/2016:$0.99
000000006:Orange Juice:$2.99:398:03/11/2015:03/11/2016:$1.99
000000007:Potatoes:$2.99:792:03/11/2015:03/11/2016:$1.99
000000008:Celery:$0.99:973:03/11/2015:03/11/2016:$0.99
000000009:Onions:$1.99:763:03/11/2015:03/11/2016:$0.99
000000010:Chicken:$8.99:345:03/11/2015:03/11/2016:$7.99
000000010:Chicken:$8.99:345:03/11/2015:03/11/2016:$7.99
I need to get the value of each of the "quantity" values from the position in bold.
EDIT:
I want to also compare the values that I got and give an error if the quantity is low.

Solution with minimal memory consumption in case of large input data.
In additional: there are not processing of incorrect data in quantity column. To do this just replace int.Parse block;
This is several methods to process file data using LINQ expressions
internal static class MyExtensions
{
/// <exception cref="OutOfMemoryException">There is insufficient memory to allocate a buffer for the returned string. </exception>
/// <exception cref="IOException">An I/O error occurs. </exception>
/// <exception cref="ArgumentException"><paramref name="stream" /> does not support reading. </exception>
/// <exception cref="ArgumentNullException"><paramref name="stream" /> is null. </exception>
public static IEnumerable<string> EnumerateLines(this Stream stream)
{
using (var reader = new StreamReader(stream))
{
do
{
var line = reader.ReadLine();
if (line == null) break;
yield return line;
} while (true);
}
}
/// <exception cref="ArgumentNullException"><paramref name="line"/> is <see langword="null" />.</exception>
public static IEnumerable<string> ChunkLine(this string line)
{
if (line == null) throw new ArgumentNullException("line");
return line.Split(':');
}
/// <exception cref="ArgumentNullException"><paramref name="chuckedData"/> is <see langword="null" />.</exception>
/// <exception cref="ArgumentException">Index should be not negative value</exception>
public static string GetColumnData(this IEnumerable<string> chuckedData, int columnIndex)
{
if (chuckedData == null) throw new ArgumentNullException("chuckedData");
if (columnIndex < 0) throw new ArgumentException("Column index should be >= 0", "columnIndex");
return chuckedData.Skip(columnIndex).FirstOrDefault();
}
}
This is example of usage:
private void button1_Click(object sender, EventArgs e)
{
var values = EnumerateQuantityValues("largefile.txt");
// do whatever you need
}
private IEnumerable<int> EnumerateQuantityValues(string fileName)
{
const int columnIndex = 3;
using (var stream = File.OpenRead(fileName))
{
IEnumerable<int> enumerable = stream
.EnumerateLines()
.Select(x => x.ChunkLine().GetColumnData(columnIndex))
.Select(int.Parse);
foreach (var value in enumerable)
{
yield return value;
}
}
}

just consider if you are managed to get all these lines in string array or list.
you can apply the below code to get the collection of quantity as IEnumerable<string>.
var quantity = arr.Select(c =>
{
var temp = c.Split('$');
if (temp.Length > 1)
{
temp = temp[1].Split(':');
if (temp.Length > 1)
{
return temp[1];
}
}
return null;
}).Where(c => c != null);
UPDATE
Check the Fiddle.
https://dotnetfiddle.net/HqKdeI

you simply need to split the string
string data = #"000000000:Carrots:$1.99:214:03/11/2015:03/11/2016:$0.99
000000001:Bananas:$1.99:872:03/11/2015:03/11/2016:$0.99
000000002:Chocolate:$2.99:083:03/11/2015:03/11/2016:$1.99
000000003:Spaghetti:$3.99:376:03/11/2015:03/11/2016:$2.99
000000004:Tomato Sauce:$1.99:437:03/11/2015:03/11/2016:$0.99
000000005:Lettuce:$0.99:279:03/11/2015:03/11/2016:$0.99
000000006:Orange Juice:$2.99:398:03/11/2015:03/11/2016:$1.99
000000007:Potatoes:$2.99:792:03/11/2015:03/11/2016:$1.99
000000008:Celery:$0.99:973:03/11/2015:03/11/2016:$0.99
000000009:Onions:$1.99:763:03/11/2015:03/11/2016:$0.99
000000010:Chicken:$8.99:345:03/11/2015:03/11/2016:$7.99";
string[] rows = data.split(Environment.Newline.ToCharArray());
foreach(var row in rows)
{
string[] cols = row.Split(':');
var quantity = cols[3];
}

You can use String.Split to do this.
// Read all lines into an array
string[] lines = File.ReadAllLines(#"C:\path\to\your\file.txt");
// Loop through each one
foreach (string line in lines)
{
// Split into an array based on the : symbol
string[] split = line.Split(':');
// Get the column based on index
Console.WriteLine(split[3]);
}

Check out the example code below. The string you care about is named theValueYouWantInTheString.
char[] delimiterChar = { ':' };
string input = #"000000010:Chicken:$8.99:345:03/11/2015:03/11/2016:$7.99";
string[] values = input.Split(delimiterChar);
string theValueYouWantInTheString = values[3];

If you have a problem, use regular expression. Now you have two problems.
Here is a program that uses your input as a txt file. The function GetQuantity returns a list with int that contains the quantity. With this approach you can define more groups to extract information from each line.
namespace RegExptester
{
class Program
{
private static List<int> GetQuantity(string txtFile)
{
string tempLineValue;
Regex regex = new Regex(#"[0-9]*:[a-zA-Z]*:\$[0-9]*\.[0-9]*:([0-9]*).*", RegexOptions.Compiled);
List<int> retValue = new List<int>();
using (StreamReader inputReader = new StreamReader(txtFile))
{
while (null != (tempLineValue = inputReader.ReadLine()))
{
Match match = regex.Match(tempLineValue);
if (match.Success)
{
if(match.Groups.Count == 2)
{
int numberValue;
if (int.TryParse(match.Groups[1].Value, out numberValue))
retValue.Add(numberValue);
}
}
}
}
return retValue;
}
static void Main(string[] args)
{
var tmp = GetQuantity("c:\\tmp\\junk.txt");
}
}
}

Apparently from each line you want the part between the 3th and the 4th colon. Linq can do that for you:
using (var textReader = new StreamReader(fileName))
{
// read all text and divide into lines:
var allText = textReader.ReadToEnd();
var allLines = textReader.Split(new char[] {'\r','\n'}, StringSplitIoptions.RemoveEmptyEntries);
// split each line based on ':', and take the fourth element
var myValues = allLines.Select(line => line.Split(new char[] {':'})
.Skip(3)
.FirstOrDefault();
}
If you want less readability, of course you can concatenate these statements into one line.

Counting/sorting characters in a text file

I am trying to write a program that reads a text file, sorts it by character, and keeps track of how many times each character appears in the document. This is what I have so far.
class Program
{
static void Main(string[] args)
{
CharFrequency[] Charfreq = new CharFrequency[128];
try
{
string line;
System.IO.StreamReader file = new System.IO.StreamReader(#"C:\Users\User\Documents\Visual Studio 2013\Projects\Array_Project\wap.txt");
while ((line = file.ReadLine()) != null)
{
int ch = file.Read();
if (Charfreq.Contains(ch))
{
}
}
file.Close();
Console.ReadLine();
}
catch (Exception e)
{
Console.WriteLine("The process failed: {0}", e.ToString());
}
}
}
My question is, what should go in the if statement here?
I also have a Charfrequency class, which I'll include here in case it is helpful/necessary that I include it (and yes, it is necessary that I use an array versus a list or arraylist).
public class CharFrequency
{
private char m_character;
private long m_count;
public CharFrequency(char ch)
{
Character = ch;
Count = 0;
}
public CharFrequency(char ch, long charCount)
{
Character = ch;
Count = charCount;
}
public char Character
{
set
{
m_character = value;
}
get
{
return m_character;
}
}
public long Count
{
get
{
return m_count;
}
set
{
if (value < 0)
value = 0;
m_count = value;
}
}
public void Increment()
{
m_count++;
}
public override bool Equals(object obj)
{
bool equal = false;
CharFrequency cf = new CharFrequency('\0', 0);
cf = (CharFrequency)obj;
if (this.Character == cf.Character)
equal = true;
return equal;
}
public override int GetHashCode()
{
return m_character.GetHashCode();
}
public override string ToString()
{
String s = String.Format("'{0}' ({1}) = {2}", m_character, (byte)m_character, m_count);
return s;
}
}

Have a look at this post.
https://codereview.stackexchange.com/questions/63872/counting-the-number-of-character-occurrences
It uses LINQ to achieve your goal

You shouldn't use Contains
first you need to initialize your Charfreq array:
CharFrequency[] Charfreq = new CharFrequency[128];
for (int i = 0; i < Charferq.Length; i++)
{
Charfreq[i] = new CharFrequency((char)i);
}
try
then you can
int ch;
// -1 means that there are no more characters to read,
// otherwise ch is the char read
while ((ch = file.Read()) != -1)
{
CharFrequency cf = new CharFrequency((char)ch);
// This works because CharFrequency overloads the
// Equals method, and the Equals method checks only
// for the Character property of CharFrequency
int ix = Array.IndexOf(Charfreq, cf);
// if there is the "right" charfrequency
if (ix != -1)
{
Charfreq[ix].Increment();
}
}
Note that this isn't the way I would write the program. This is the minimum changes needed to make your program working.
As a sidenote, this program will count the "frequency" of ASCII characters (characters with code <= 127)
CharFrequency cf = new CharFrequency('\0', 0);
cf = (CharFrequency)obj;
And this is an useless initialization:
CharFrequency cf = (CharFrequency)obj;
is enough, otherwise you are creating a CharFrequency just to discard it the line below.

A dictionary is well suited for a task like this. You didn't say which character set and encoding the file was in. So, because Unicode is so common, let's assume the Unicode character set and UTF-8 encoding. (After all, it is the default for .NET, Java, JavaScript, HTML, XML,….) If that's not the case then read the file using the applicable encoding and fix your code because you currently are using UTF-8 in your StreamReader.
Next comes iterating across the "characters". And then incrementing the count for a "character" in the dictionary as it is seen in the text.
Unicode does have a few complex features. One is combining characters, where a base character can be overlaid with diacritics etc. Users view such combinations as one "character", or, as Unicode calls them, graphemes. Thankfully, .NET gives is the StringInfo class that iterates over them as a "text element."
So, if you think about it, using an array would be quite difficult. You'd have to build your own dictionary on top of your array.
The example below uses a Dictionary and is runnable using a LINQPad script. After it creates the dictionary, it orders and dumps it with a nice display.
var path = Path.GetTempFileName();
// Get some text we know is encoded in UTF-8 to simplify the code below
// and contains combining codepoints as a matter of example.
using (var web = new WebClient())
{
web.DownloadFile("http://superuser.com/questions/52671/which-unicode-characters-do-smilies-like-%D9%A9-%CC%AE%CC%AE%CC%83-%CC%83%DB%B6-consist-of", path);
}
// since the question asks to analyze a file
var content = File.ReadAllText(path, Encoding.UTF8);
var frequency = new Dictionary<String, int>();
var itor = System.Globalization.StringInfo.GetTextElementEnumerator(content);
while (itor.MoveNext())
{
var element = (String)itor.Current;
if (!frequency.ContainsKey(element))
{
frequency.Add(element, 0);
}
frequency[element]++;
}
var histogram = frequency
.OrderByDescending(f => f.Value)
// jazz it up with the list of codepoints in each text element
.Select(pair =>
{
var bytes = Encoding.UTF32.GetBytes(pair.Key);
var codepoints = new UInt32[bytes.Length/4];
Buffer.BlockCopy(bytes, 0, codepoints, 0, bytes.Length);
return new {
Count = pair.Value,
textElement = pair.Key,
codepoints = codepoints.Select(cp => String.Format("U+{0:X4}", cp) ) };
});
histogram.Dump(); // For use in LINQPad

Regex camelcase in c#

I'm trying to use regex to convert a string like this "North Korea"
to a string like "northKorea" - does someone know how I might accomplish this in c# ?
Cheers

if you know all your input strings are in title case (like "North Korea") you can simply do:
string input = "North Korea";
input = input.Replace(" ",""); //remove spaces
string output = char.ToLower(input[0]) +
input.Substring(1); //make first char lowercase
// output = "northKorea"
if some of your input is not in title case you can use TextInfo.ToTitleCase
string input = "NoRtH kORea";
input = System.Globalization.CultureInfo.CurrentCulture.TextInfo.ToTitleCase(input);
input = input.Replace(" ",""); //remove spaces
string output = char.ToLower(input[0]) +
input.Substring(1); //make first char lowercase
// output = "northKorea"

Forget regex.
All you need is a camelCase conversion algorithm:
See here:
http://www.codekeep.net/snippets/096fea45-b426-40fd-8beb-dec49d8a8662.aspx
Use this one:
string camelCase = ConvertCaseString(a, Case.CamelCase);
Copy-pasted in case it goes offline:
void Main() {
string a = "background color-red.brown";
string camelCase = ConvertCaseString(a, Case.CamelCase);
string pascalCase = ConvertCaseString(a, Case.PascalCase);
}
/// <summary>
/// Converts the phrase to specified convention.
/// </summary>
/// <param name="phrase"></param>
/// <param name="cases">The cases.</param>
/// <returns>string</returns>
static string ConvertCaseString(string phrase, Case cases)
{
string[] splittedPhrase = phrase.Split(' ', '-', '.');
var sb = new StringBuilder();
if (cases == Case.CamelCase)
{
sb.Append(splittedPhrase[0].ToLower());
splittedPhrase[0] = string.Empty;
}
else if (cases == Case.PascalCase)
sb = new StringBuilder();
foreach (String s in splittedPhrase)
{
char[] splittedPhraseChars = s.ToCharArray();
if (splittedPhraseChars.Length > 0)
{
splittedPhraseChars[0] = ((new String(splittedPhraseChars[0], 1)).ToUpper().ToCharArray())[0];
}
sb.Append(new String(splittedPhraseChars));
}
return sb.ToString();
}
enum Case
{
PascalCase,
CamelCase
}

You could just split it and put it back together:
string[] split = ("North Korea").Split(' ');
StringBuilder sb = new StringBuilder();
for (int i = 0; i < split.Count(); i++)
{
if (i == 0)
sb.Append(split[i].ToLower());
else
sb.Append(split[i]);
}
Edit: Switched to a StringBuilder instead, like Bazzz suggested.

This builds on Paolo Falabella's answer as a String extension and handles a few boundary cases such as empty string. Since there is some confusion between CamelCase and camelCase, I called it LowerCamelCase as described on Wikipedia. I resisted the temptation to go with nerdCaps.
internal static string ToLowerCamelCase( this string input )
{
string output = "";
if( String.IsNullOrEmpty( input ) == false )
{
output = System.Globalization.CultureInfo.CurrentCulture.TextInfo.ToTitleCase( input ); //in case not Title Case
output = output.Replace( " ", "" ); //remove any white spaces between words
if( String.IsNullOrEmpty( output ) == false ) //handles the case where input is " "
{
output = char.ToLower( output[0] ) + output.Substring( 1 ); //lowercase first (even if 1 character string)
}
}
return output;
}
Use:
string test = "Foo Bar";
test = test.ToLowerCamelCase();
... //test is now "fooBar"
Update:
toong raised a good point in the comments - this will not work for graphemes. See the link provided by toong. There are also examples of iterating graphemes here and here if you want to tweak the above code for graphemes.

String::Split definitely is one of my pet peeves. Also, none of the other answers deal with:
Cultures
All forms of word seperators
Numbers
What happens when it starts with word seperators
I tried to get it as close as possible to what you would find in base class library code:
static string ToCamelCaseInvariant(string value) { return ToCamelCase(value, true, CultureInfo.InvariantCulture); }
static string ToCamelCaseInvariant(string value, bool changeWordCaps) { return ToCamelCase(value, changeWordCaps, CultureInfo.InvariantCulture); }
static string ToCamelCase(string value) { return ToCamelCase(value, true, CultureInfo.CurrentCulture); }
static string ToCamelCase(string value, bool changeWordCaps) { return ToCamelCase(value, changeWordCaps, CultureInfo.CurrentCulture); }
/// <summary>
/// Converts the given string value into camelCase.
/// </summary>
/// <param name="value">The value.</param>
/// <param name="changeWordCaps">If set to <c>true</c> letters in a word (apart from the first) will be lowercased.</param>
/// <param name="culture">The culture to use to change the case of the characters.</param>
/// <returns>
/// The camel case value.
/// </returns>
static string ToCamelCase(string value, bool changeWordCaps, CultureInfo culture)
{
if (culture == null)
throw new ArgumentNullException("culture");
if (string.IsNullOrEmpty(value))
return value;
var result = new StringBuilder(value.Length);
var lastWasBreak = true;
for (var i = 0; i < value.Length; i++)
{
var c = value[i];
if (char.IsWhiteSpace(c) || char.IsPunctuation(c) || char.IsSeparator(c))
{
lastWasBreak = true;
}
else if (char.IsNumber(c))
{
result.Append(c);
lastWasBreak = true;
}
else
{
if (result.Length == 0)
{
result.Append(char.ToLower(c, culture));
}
else if (lastWasBreak)
{
result.Append(char.ToUpper(c, culture));
}
else if (changeWordCaps)
{
result.Append(char.ToLower(c, culture));
}
else
{
result.Append(c);
}
lastWasBreak = false;
}
}
return result.ToString();
}
// Tests
' This is a test. 12345hello world' = 'thisIsATest12345HelloWorld'
'--north korea' = 'northKorea'
'!nOrTH koreA' = 'northKorea'
'System.Console.' = 'systemConsole'

Try the following:
var input = "Hi my name is Rony";
var subStrs = input.ToLower().Split(' ');
var output = "";
foreach(var s in subStrs)
{
if(s!=subStrs[0])
output += s.First().ToString().ToUpper() + String.Join("", s.Skip(1));
else
output += s;
}
should get "hiMyNameIsRony" as the output

string toCamelCase(string s)
{
if (s.Length < 2) return s.ToLower();
return Char.ToLowerInvariant(s[0]) + s.Substring(1);
}
similar to Paolo Falabella's code but survives empty strings and 1 char strings.

escaping tricky string to CSV format

I have to create a CSV file from webservice output and the CSV file uses quoted strings with comma separator. I cannot change the format...
So if I have a string it becomes a "string"...
If the value has quotes already they are replaced with double quotes.
For example a str"ing becomes "str""ing"...
However, lately my import has been failing because of the following
original input string is: "","word1,word2,..."
every single quote is replaced by double resulting in: """",""word1,word2,...""
then its prefixed and suffixed with quote before written to CVS file: """"",""word1,word2,..."""
As you can see the final result is this:
""""",""word1,word2,..."""
which breaks my import (is sees it as another field)...
I think the issue is appereance of "," in the original input string.
Is there a CVS escape sequence for this scenario?
Update
The reason why above breaks is due to BCP mapping file (BCP utility is used to load CSV file into SQL db) which has terminator defined as "," . So instead of seeing 1 field it sees 2...But I cannot change the mapping file...

I use this code and it has always worked:
/// <summary>
/// Turn a string into a CSV cell output
/// </summary>
/// <param name="str">String to output</param>
/// <returns>The CSV cell formatted string</returns>
public static string StringToCSVCell(string str)
{
bool mustQuote = (str.Contains(",") || str.Contains("\"") || str.Contains("\r") || str.Contains("\n"));
if (mustQuote)
{
StringBuilder sb = new StringBuilder();
sb.Append("\"");
foreach (char nextChar in str)
{
sb.Append(nextChar);
if (nextChar == '"')
sb.Append("\"");
}
sb.Append("\"");
return sb.ToString();
}
return str;
}

Based on Ed Bayiates' answer:
/// <summary>
/// Turn a string into a CSV cell output
/// </summary>
/// <param name="value">String to output</param>
/// <returns>The CSV cell formatted string</returns>
private string ConvertToCsvCell(string value)
{
var mustQuote = value.Any(x => x == ',' || x == '\"' || x == '\r' || x == '\n');
if (!mustQuote)
{
return value;
}
value = value.Replace("\"", "\"\"");
return string.Format("\"{0}\"", value);
}

My penny thought:
String[] lines = new String[] { "\"\",\"word\",word,word2,1,34,5,2,\"details\"" };
for (int j = 0; j < lines.Length; j++)
{
String[] fields=lines[j].Split(',');
for (int i =0; i<fields.Length; i++)
{
if (fields[i].StartsWith("\"") && fields[i].EndsWith("\""))
{
char[] tmp = new char[fields[i].Length-2];
fields[i].CopyTo(1,tmp,0,fields[i].Length-2);
fields[i] =tmp.ToString();
fields[i] = "\""+fields[i].Replace("\"","\"\"")+"\"";
}
else
fields[i] = fields[i].Replace("\"","\"\"");
}
lines[j]=String.Join(",",fields);
}

Based on contribution of "Ed Bayiates" here's an helpful class to buid csv document:
/// <summary>
/// helpful class to build csv document
/// </summary>
public class CsvBuilder
{
/// <summary>
/// create the csv builder
/// </summary>
public CsvBuilder(char csvSeparator)
{
m_csvSeparator = csvSeparator;
}
/// <summary>
/// append a cell
/// </summary>
public void appendCell(string strCellValue)
{
if (m_nCurrentColumnIndex > 0) m_strBuilder.Append(m_csvSeparator);
bool mustQuote = (strCellValue.Contains(m_csvSeparator)
|| strCellValue.Contains('\"')
|| strCellValue.Contains('\r')
|| strCellValue.Contains('\n'));
if (mustQuote)
{
m_strBuilder.Append('\"');
foreach (char nextChar in strCellValue)
{
m_strBuilder.Append(nextChar);
if (nextChar == '"') m_strBuilder.Append('\"');
}
m_strBuilder.Append('\"');
}
else
{
m_strBuilder.Append(strCellValue);
}
m_nCurrentColumnIndex++;
}
/// <summary>
/// end of line, new line
/// </summary>
public void appendNewLine()
{
m_strBuilder.Append(Environment.NewLine);
m_nCurrentColumnIndex = 0;
}
/// <summary>
/// Create the CSV file
/// </summary>
/// <param name="path"></param>
public void save(string path )
{
File.WriteAllText(path, ToString());
}
public override string ToString()
{
return m_strBuilder.ToString();
}
private StringBuilder m_strBuilder = new StringBuilder();
private char m_csvSeparator;
private int m_nCurrentColumnIndex = 0;
}
How to use it:
void exportAsCsv( string strFileName )
{
CsvBuilder csvStringBuilder = new CsvBuilder(';');
csvStringBuilder.appendCell("#Header col 1 : Name");
csvStringBuilder.appendCell("col 2 : Value");
csvStringBuilder.appendNewLine();
foreach (Data data in m_dataSet)
{
csvStringBuilder.appendCell(data.getName());
csvStringBuilder.appendCell(data.getValue());
csvStringBuilder.appendNewLine();
}
csvStringBuilder.save(strFileName);
}

the first step in parsing this is removing the extra added " 's around your string. Once you do this, you should be able to deal with the embedded " as well as the ,'s.

After much deliberation, it was decided that import utility format was needed to be fixed. The escaping of the string was correct (as users indicated) but the format file that import utility used was incorrect and was causing it to break import.
Thanks all and special thanks to #dbt (up vote)

How to check if directory 1 is a subdirectory of dir2 and vice versa

What is an easy way to check if directory 1 is a subdirectory of directory 2 and vice versa?
I checked the Path and DirectoryInfo helperclasses but found no system-ready function for this. I thought it would be in there somewhere.
Do you guys have an idea where to find this?
I tried writing a check myself, but it's more complicated than I had anticipated when I started.

In response to the first part of the question: "Is dir1 a sub-directory of dir2?", this code should work:
public bool IsSubfolder(string parentPath, string childPath)
{
var parentUri = new Uri(parentPath);
var childUri = new DirectoryInfo(childPath).Parent;
while (childUri != null)
{
if(new Uri(childUri.FullName) == parentUri)
{
return true;
}
childUri = childUri.Parent;
}
return false;
}
The URIs (on Windows at least, might be different on Mono/Linux) are case-insensitive. If case sensitivity is important, use the Compare method on Uri instead.

Here's a simpler way to do it using the Uri class:
var parentUri = new Uri(parentPath);
var childUri = new Uri(childPath);
if (parentUri != childUri && parentUri.IsBaseOf(childUri))
{
//dowork
}

See original answer here: https://stackoverflow.com/a/31941159/134761
Case insensitive
Tolerates mix of \ and / folder delimiters
Tolerates ..\ in path
Avoids matching on partial folder names (c:\foobar not a subpath of c:\foo)
Code:
public static class StringExtensions
{
/// <summary>
/// Returns true if <paramref name="path"/> starts with the path <paramref name="baseDirPath"/>.
/// The comparison is case-insensitive, handles / and \ slashes as folder separators and
/// only matches if the base dir folder name is matched exactly ("c:\foobar\file.txt" is not a sub path of "c:\foo").
/// </summary>
public static bool IsSubPathOf(this string path, string baseDirPath)
{
string normalizedPath = Path.GetFullPath(path.Replace('/', '\\')
.WithEnding("\\"));
string normalizedBaseDirPath = Path.GetFullPath(baseDirPath.Replace('/', '\\')
.WithEnding("\\"));
return normalizedPath.StartsWith(normalizedBaseDirPath, StringComparison.OrdinalIgnoreCase);
}
/// <summary>
/// Returns <paramref name="str"/> with the minimal concatenation of <paramref name="ending"/> (starting from end) that
/// results in satisfying .EndsWith(ending).
/// </summary>
/// <example>"hel".WithEnding("llo") returns "hello", which is the result of "hel" + "lo".</example>
public static string WithEnding([CanBeNull] this string str, string ending)
{
if (str == null)
return ending;
string result = str;
// Right() is 1-indexed, so include these cases
// * Append no characters
// * Append up to N characters, where N is ending length
for (int i = 0; i <= ending.Length; i++)
{
string tmp = result + ending.Right(i);
if (tmp.EndsWith(ending))
return tmp;
}
return result;
}
/// <summary>Gets the rightmost <paramref name="length" /> characters from a string.</summary>
/// <param name="value">The string to retrieve the substring from.</param>
/// <param name="length">The number of characters to retrieve.</param>
/// <returns>The substring.</returns>
public static string Right([NotNull] this string value, int length)
{
if (value == null)
{
throw new ArgumentNullException("value");
}
if (length < 0)
{
throw new ArgumentOutOfRangeException("length", length, "Length is less than zero");
}
return (length < value.Length) ? value.Substring(value.Length - length) : value;
}
}
Test cases (NUnit):
[TestFixture]
public class StringExtensionsTest
{
[TestCase(#"c:\foo", #"c:", Result = true)]
[TestCase(#"c:\foo", #"c:\", Result = true)]
[TestCase(#"c:\foo", #"c:\foo", Result = true)]
[TestCase(#"c:\foo", #"c:\foo\", Result = true)]
[TestCase(#"c:\foo\", #"c:\foo", Result = true)]
[TestCase(#"c:\foo\bar\", #"c:\foo\", Result = true)]
[TestCase(#"c:\foo\bar", #"c:\foo\", Result = true)]
[TestCase(#"c:\foo\a.txt", #"c:\foo", Result = true)]
[TestCase(#"c:\FOO\a.txt", #"c:\foo", Result = true)]
[TestCase(#"c:/foo/a.txt", #"c:\foo", Result = true)]
[TestCase(#"c:\foobar", #"c:\foo", Result = false)]
[TestCase(#"c:\foobar\a.txt", #"c:\foo", Result = false)]
[TestCase(#"c:\foobar\a.txt", #"c:\foo\", Result = false)]
[TestCase(#"c:\foo\a.txt", #"c:\foobar", Result = false)]
[TestCase(#"c:\foo\a.txt", #"c:\foobar\", Result = false)]
[TestCase(#"c:\foo\..\bar\baz", #"c:\foo", Result = false)]
[TestCase(#"c:\foo\..\bar\baz", #"c:\bar", Result = true)]
[TestCase(#"c:\foo\..\bar\baz", #"c:\barr", Result = false)]
public bool IsSubPathOfTest(string path, string baseDirPath)
{
return path.IsSubPathOf(baseDirPath);
}
}
Update 2015-08-18: Fix bug matching on partial folder names. Add test cases.
Update 2016-01-29: Link to original question https://stackoverflow.com/a/31941159/134761

DirectoryInfo has a property Parent which is also a DirectoryInfo type. You can use that to to determine if your directory is a subdirectory of a parent directory.

The second directories(d2) full name will contain the full name of the first directory(d1) if it is a sub-folder of d1.
This assumes that you are using valid directories
if (d2.FullName.Contains(d1.FullName))
{
//dowork
}
If you need to check for mapped drives you could try
static void Main(string[] args)
{
if (GetUNCPath(d2.FullName).ToLower().Contains(GetUNCPath(d1.FullName).ToLower()))
{
}
}
[DllImport("mpr.dll", CharSet = CharSet.Unicode, SetLastError = true)]
private static extern int WNetGetConnection(
[MarshalAs(UnmanagedType.LPTStr)] string localName,
[MarshalAs(UnmanagedType.LPTStr)] StringBuilder remoteName, ref int length);
private static string GetUNCPath(string originalPath)
{
StringBuilder sb = new StringBuilder(512);
int size = sb.Capacity;
// look for the {LETTER}: combination ...
if (originalPath.Length > 2 && originalPath[1] == ':')
{
// don't use char.IsLetter here - as that can be misleading
// the only valid drive letters are a-z && A-Z.
char c = originalPath[0];
if ((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z'))
{
int error = WNetGetConnection(originalPath.Substring(0, 2), sb, ref size);
if (error == 0)
{
DirectoryInfo dir = new DirectoryInfo(originalPath);
string path = Path.GetFullPath(originalPath).Substring(Path.GetPathRoot(originalPath).Length);
return Path.Combine(sb.ToString().TrimEnd(), path);
}
}
}
return originalPath;
}
Code for mapped drive taken from http://social.msdn.microsoft.com/Forums/en/csharpgeneral/thread/6f79f2b3-d092-431f-bc28-d15d93cf5d09

If you have two path then look at this:
Normalize directory names in C#
http://filedirectorypath.codeplex.com/ (I don't know the quality of it)
And use this:
var ancestor = new DirectoryPathAbsolute(ancestorPath);
var child = new DirectoryPathAbsolute(childPath);
var res = child.IsChildDirectoryOf(ancestor); //I don't think it actually checks for case-sensitive filesystems
Otherwise, if you want to know whether a directory exists as a subdirectory in a path take a look on:
Directory.EnumerateDirectories
Came in .Net 4.0. Example:
Does path contain a directory starting with Console:
//* is a wildcard. If you remove it, it search for directories called "Console"
var res = Directory.EnumerateDirectories(#path, "Console*", SearchOption.AllDirectories).Any();

public static bool IsSubfolder(DirectoryInfo parentPath, DirectoryInfo childPath)
{
return parentPath.FullName.StartsWith(childPath.FullName+Path.DirectorySeparatorChar);
}

You can use Path.GetDirectoryName Method to get parent directory. It works for directories too.

With help from the great test cases written in angularsen's answer, I wrote the following simpler extension method on .NET Core 3.1 for Windows:
public static bool IsSubPathOf(this string dirPath, string baseDirPath, StringComparison comparisonType = StringComparison.OrdinalIgnoreCase)
{
dirPath = dirPath.Replace(Path.AltDirectorySeparatorChar, Path.DirectorySeparatorChar);
if (!dirPath.EndsWith(Path.DirectorySeparatorChar))
{
dirPath += Path.DirectorySeparatorChar;
}
baseDirPath = baseDirPath.Replace(Path.AltDirectorySeparatorChar, Path.DirectorySeparatorChar);
if (!baseDirPath.EndsWith(Path.DirectorySeparatorChar))
{
baseDirPath += Path.DirectorySeparatorChar;
}
string dirPathUri = new Uri(dirPath).LocalPath;
string baseDirUri = new Uri(baseDirPath).LocalPath;
return dirPathUri.Contains(baseDirUri, comparisonType);
}

this is what I got, after first verifying that the two directory path strings are something and in a path format I know something about: shouldnotbechilddirpath.ToUpper().StartsWith(maybeparentdirpath.ToUpper())
Be sure to take out the ToUppers() if you are maybe working in a case sensitive file system.

You can compare directory2 to directory1's Parent property when using a DirectoryInfo in both cases.
DirectoryInfo d1 = new DirectoryInfo(#"C:\Program Files\MyApp");
DirectoryInfo d2 = new DirectoryInfo(#"C:\Program Files\MyApp\Images");
if(d2.Parent.FullName == d1.FullName)
{
Console.WriteLine ("Sub directory");
}