如何解析一个月的名称(字符串)为一个整数进行比较在 C # ？

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If you are using c# 3.0 (or above) you can use extenders

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最佳答案

DateTime.ParseExact(monthName, "MMMM", CultureInfo.CurrentCulture ).Month

Although, for your purposes, you'll probably be better off just creating a Dictionary<string, int> mapping the month's name to its value.

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You could do something like this:

Convert.ToDate(month + " 01, 1900").Month

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You can use the DateTime.Parse method to get a DateTime object and then check its Month property. Do something like this:

int month = DateTime.Parse("1." + monthName + " 2008").Month;

The trick is to build a valid date to create a DateTime object.

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You can use an enum of months:

public enum Month
{
January,
February,
// (...)
December,
}


public Month ToInt(Month Input)
{
return (int)Enum.Parse(typeof(Month), Input, true));
}

I am not 100% certain on the syntax for enum.Parse(), though.

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If you use the DateTime.ParseExact()-method that several people have suggested, you should carefully consider what you want to happen when the application runs in a non-English environment!

In Denmark, which of ParseExact("Januar", ...) and ParseExact("January", ...) should work and which should fail?

That will be the difference between CultureInfo.CurrentCulture and CultureInfo.InvariantCulture.

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Public Function returnMonthNumber(ByVal monthName As String) As Integer
Select Case monthName.ToLower
Case Is = "january"
Return 1
Case Is = "february"
Return 2
Case Is = "march"
Return 3
Case Is = "april"
Return 4
Case Is = "may"
Return 5
Case Is = "june"
Return 6
Case Is = "july"
Return 7
Case Is = "august"
Return 8
Case Is = "september"
Return 9
Case Is = "october"
Return 10
Case Is = "november"
Return 11
Case Is = "december"
Return 12
Case Else
Return 0
End Select
End Function

caution code is in Beta version.

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What I did was to use SimpleDateFormat to create a format string, and parse the text to a date, and then retrieve the month from that. The code is below:

int year = 2012 \\or any other year
String monthName = "January" \\or any other month
SimpleDateFormat format = new SimpleDateFormat("dd-MMM-yyyy");
int monthNumber = format.parse("01-" + monthName + "-" + year).getMonth();

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You don't have to create a DateTime instance to do this. It's as simple as this:

public static class Month
{
public static int ToInt(this string month)
{
return Array.IndexOf(
CultureInfo.CurrentCulture.DateTimeFormat.MonthNames,
month.ToLower(CultureInfo.CurrentCulture))
+ 1;
}
}

I'm running on the da-DK culture, so this unit test passes:

[Theory]
[InlineData("Januar", 1)]
[InlineData("Februar", 2)]
[InlineData("Marts", 3)]
[InlineData("April", 4)]
[InlineData("Maj", 5)]
[InlineData("Juni", 6)]
[InlineData("Juli", 7)]
[InlineData("August", 8)]
[InlineData("September", 9)]
[InlineData("Oktober", 10)]
[InlineData("November", 11)]
[InlineData("December", 12)]
public void Test(string monthName, int expected)
{
var actual = monthName.ToInt();
Assert.Equal(expected, actual);
}

I'll leave it as an exercise to the reader to create an overload where you can pass in an explicit CultureInfo.

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I translate it into C# code in Spanish version, regards:

public string ObtenerNumeroMes(string NombreMes){


string NumeroMes;


switch(NombreMes) {


case ("ENERO") :
NumeroMes = "01";
return NumeroMes;


case ("FEBRERO") :
NumeroMes = "02";
return NumeroMes;


case ("MARZO") :
NumeroMes = "03";
return NumeroMes;


case ("ABRIL") :
NumeroMes = "04";
return NumeroMes;


case ("MAYO") :
NumeroMes = "05";
return NumeroMes;


case ("JUNIO") :
NumeroMes = "06";
return NumeroMes;


case ("JULIO") :
NumeroMes = "07";
return NumeroMes;


case ("AGOSTO") :
NumeroMes = "08";
return NumeroMes;


case ("SEPTIEMBRE") :
NumeroMes = "09";
return NumeroMes;


case ("OCTUBRE") :
NumeroMes = "10";
return NumeroMes;


case ("NOVIEMBRE") :
NumeroMes = "11";
return NumeroMes;


case ("DICIEMBRE") :
NumeroMes = "12";
return NumeroMes;


default:
Console.WriteLine("Error");
return "ERROR";


}


}

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One simply solution would be create a Dictionary with names and values. Then using Contains() you can find the right value.

Dictionary<string, string> months = new Dictionary<string, string>()
{
{ "january", "01"},
{ "february", "02"},
{ "march", "03"},
{ "april", "04"},
{ "may", "05"},
{ "june", "06"},
{ "july", "07"},
{ "august", "08"},
{ "september", "09"},
{ "october", "10"},
{ "november", "11"},
{ "december", "12"},
};
foreach (var month in months)
{
if (StringThatContainsMonth.ToLower().Contains(month.Key))
{
string thisMonth = month.Value;
}
}

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And answering this seven years after the question was asked, it is possible to do this comparison using built-in methods:

Month.toInt("January") > Month.toInt("May")

becomes

Array.FindIndex( CultureInfo.CurrentCulture.DateTimeFormat.MonthNames,
t => t.Equals("January", StringComparison.CurrentCultureIgnoreCase)) >
Array.FindIndex( CultureInfo.CurrentCulture.DateTimeFormat.MonthNames,
t => t.Equals("May", StringComparison.CurrentCultureIgnoreCase))

Which can be refactored into an extension method for simplicity. The following is a LINQPad example (hence the Dump() method calls):

void Main()
{
("January".GetMonthIndex() > "May".GetMonthIndex()).Dump();
("January".GetMonthIndex() == "january".GetMonthIndex()).Dump();
("January".GetMonthIndex() < "May".GetMonthIndex()).Dump();
}


public static class Extension {
public static int GetMonthIndex(this string month) {
return Array.FindIndex( CultureInfo.CurrentCulture.DateTimeFormat.MonthNames,
t => t.Equals(month, StringComparison.CurrentCultureIgnoreCase));
}
}

With output:

False
True
True

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This code helps you...

using System.Globalization;


....


string FullMonthName = CultureInfo.CurrentCulture.DateTimeFormat.GetMonthName(DateTime.UtcNow.Month);

GetMonthName Method - it returns string...

If you want to get a month as an integer, then simply use -

DateTime dt= DateTime.UtcNow;
int month= dt.Month;

I hope, it helps you!!!

Thanks!!!

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int selectedValue = 0;
switch (curentMonth)
{
case "January":
selectedValue = 1;
break;
case "February":
selectedValue = 2;
break;
}
if (selectedValue != 0)
{
/* var list= db.model_name.Where(x => x.column== selectedValue);
return list; */
}
return Ok(selectedValue);

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This code is for awk, but easily adaptable to C/C++/C#

— in ABC0, all indices are ABC1 instead of ABC2 - the leading edge "=" of the reference string is simply pre-shifting the positions. remove that "=" for any 0-based languages`

function __(_) {  #  input - Eng. month names, any casing, min. 3 letters
# output - MM : [01-12], zero-padded
return \
((_=toupper(_)) ~ "^[OND]" ? "" : _<_) \
(index("=ANEBARPRAYUNULUGEPCTOVEC", substr(_ "",_+=_^=_<_,_))/_)
}

The reference string might look odd at first -

the 2nd + 3rd letters of month names constitute a unique set

So OP can input the english name of the months, full or abbreviated, and it'll return a zero-padded 2-digit month number. If you need it to be in integer form, then just scrub out the middle line that performs the padding.

You'll notice only 1 input variable declared and no other temp variables whatsoever - one of awk's major strengths is its extreme agility when it comes to dynamic typing of variables, even for truly illogical operations like taking the "0th-power" of a string variable like

"Boston" ^ 0

This would seamlessly coerce that variable to a numeric data type, with a new value of 1.

This flexibility enables the recycling and re-using of the input temp variable(s) for any other purpose the moment the original input value(s) is/are no longer needed.