Differences between revisions 7 and 8

Stata Numeric Functions

Stata supports these numeric functions in the global scope.

Contents

Stata Numeric Functions
1. Dhms
2. Dmy
3. Hms
4. Mdy
5. Mdyhms
6. Real
7. Runiform
8. String
9. StrOfReal
10. Y
11. Yh
12. Ym
13. Yq
14. Yw

Dhms

Convert an date value (formatted as %td) plus an hour, minute, and second into the number of milliseconds since the Stata epoch (01jan1960 00:00:00.000`) ignoring leap seconds.

generate double datetime = dhms(dmy(day, month, year), hour, minute, second)
format date %tc

See also Cdhms, which creates returns a number that should instead be formatted as %tC because it does not ignore leap seconds.

Dmy

Convert a day, month, and year into the number of days since the Stata epoch (01jan1960 00:00:00.000).

generate long date = dmy(day, month, year)
format date %td

Hms

Convert an hour, minute, and second into the number of milliseconds since midnight ignoring leap seconds.

generate double datetime = hms(hour, minute, second)
format date %tc

See also Chms, which creates returns a number that should instead be formatted as %tC because it does not ignore leap seconds.

Mdy

Convert a month, day, and year into the number of days since the Stata epoch (01jan1960 00:00:00.000).

generate long date = mdy(month, day, year)
format date %td

Mdyhms

Convert a day, month, year, hour, minute, and second into the number of milliseconds since the Stata epoch (01jan1960 00:00:00.000) ignoring leap seconds.

generate double datetime = mdyhms(month, day, year, hour, minute, second)
format date %tc

See also Cmdyhms, which creates returns a number that should instead be formatted as %tC because it does not ignore leap seconds.

Real

Runiform

runiform(a,b) returns a random number between a and b. If no parameters are specified, the defaults of 0 and 1 are used.

Below is a demonstration for how an SRS sample can be drawn.

set seed 123456
generate double r_sampled = runiform()
sort r_sampled
generate byte sampled = _n <= 100

The return value is a double; it will be within a + c(epsdouble) and b − c(epsdouble).

By default, runiform uses the 64-bit Mersenne Twister algorithm. Alternate algorithms are available; see set rng.

See also set seed for designing deterministic programs.

String

Alias for strofreal.

StrOfReal

Y

Convert a year into the number of years since the Stata epoch (01jan1960 00:00:00.000).

generate int year = y(year)
format year %ty

Yh

Convert a year and half year into the number of half years since the Stata epoch (01jan1960 00:00:00.000).

generate int halfyears = yh(year, halfyear)
format halfyears %th

Ym

Convert a year and month into the number of months since the Stata epoch (01jan1960 00:00:00.000).

generate int months = y(year, month)
format months %tm

Yq

Convert a year and quarter into the number of years since the Stata epoch (01jan1960 00:00:00.000).

generate int quarters = yq(year, quarter)
format quarters %tq

Yw

Convert a year and week into the number of weeks since the Stata epoch (01jan1960 00:00:00.000).

generate int weeks = yw(year, week)
format weeks %tw

CategoryRicottone

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+   ← Revision 8 as of 2023-06-13 23:04:14 → ⇥
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-Deletions are marked like this.
+Additions are marked like this.
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-See also `Cdhms`.
+Convert an date value (formatted as `%td) plus an hour, minute, and second into the number of milliseconds since the Stata epoch (`01jan1960 00:00:00.000`) ''ignoring'' leap seconds.

{{{
generate double datetime = dhms(dmy(day, month, year), hour, minute, second)
format date %tc
}}}

See also `Cdhms`, which creates returns a number that should instead be formatted as `%tC` because it does ''not'' ignore leap seconds.
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+Line 28:
+Convert a day, month, and year into the number of days since the Stata epoch (`01jan1960 00:00:00.000`).

{{{
generate long date = dmy(day, month, year)
format date %td
}}}
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+Line 41:
-See also `Chms`.
+Convert an hour, minute, and second into the number of milliseconds since midnight ''ignoring'' leap seconds.

{{{
generate double datetime = hms(hour, minute, second)
format date %tc
}}}

See also `Chms`, which creates returns a number that should instead be formatted as `%tC` because it does ''not'' ignore leap seconds.
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+Line 56:
+Convert a month, day, and year into the number of days since the Stata epoch (`01jan1960 00:00:00.000`).

{{{
generate long date = mdy(month, day, year)
format date %td
}}}
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+Line 69:
-See also `Cmdyhms`.
+Convert a day, month, year, hour, minute, and second into the number of milliseconds since the Stata epoch (`01jan1960 00:00:00.000`) ''ignoring'' leap seconds.
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+Line 71:
-----
+{{{
generate double datetime = mdyhms(month, day, year, hour, minute, second)
format date %tc
}}}
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+Line 76:
-== Y ==

----



== Yh ==

----



== Ym ==

----



== Yq ==

----



== Yw ==
+See also `Cmdyhms`, which creates returns a number that should instead be formatted as `%tC` because it does ''not'' ignore leap seconds.
-Line 83:
+Line 88:
-== String ==

----



== StrOfReal ==

----



== Random Number Functions ==

=== Runiform ===
+== Runiform ==
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+Line 103:
-By default, `runiform` uses the 64-bit Mersenne Twister algorithm. Alternate algorithms are available; see '''`set rng`'''.
+By default, `runiform` uses the 64-bit Mersenne Twister algorithm. Alternate algorithms are available; see [[Stata/Set#Rng|set rng]].

See also [[Stata/Set#Seed|set seed]] for designing deterministic programs.

----
-Line 116:
+Line 111:
-=== Set Rng ===
+== String ==
-Line 118:
+Line 113:
-To use an alternate random number generation algorithm, set the rng value to something other than `default`.
+Alias for `strofreal`.
-Line 120:
+Line 115:
-{{{
set rng default
}}}

Possible values include...

 * `mt64` (64-bit Mersenne Twister)
 * `mt64s` (stream algorithm based on the 64-bit Mersenne Twister)
 * `kiss32` (32-bit keep it simple stupid)

In Stata 14, the default flipped from `kiss32` to `mt64`.
+----
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+Line 119:
-=== Set Seed ===
+== StrOfReal ==
-Line 136:
+Line 121:
-To make random number generation reproducible, set a seed value.
+----



== Y ==

Convert a year into the number of years since the Stata epoch (`01jan1960 00:00:00.000`).
-Line 139:
+Line 130:
-set seed 42
+generate int year = y(year)
format year %ty
-Line 142:
+Line 134:
-A seed value must be an integer, non-negative, and no greater than 2^31^ − 1.
+----



== Yh ==

Convert a year and half year into the number of half years since the Stata epoch (`01jan1960 00:00:00.000`).

{{{
generate int halfyears = yh(year, halfyear)
format halfyears %th
}}}

----



== Ym ==

Convert a year and month into the number of months since the Stata epoch (`01jan1960 00:00:00.000`).

{{{
generate int months = y(year, month)
format months %tm
}}}

----



== Yq ==

Convert a year and quarter into the number of years since the Stata epoch (`01jan1960 00:00:00.000`).

{{{
generate int quarters = yq(year, quarter)
format quarters %tq
}}}

----



== Yw ==

Convert a year and week into the number of weeks since the Stata epoch (`01jan1960 00:00:00.000`).

{{{
generate int weeks = yw(year, week)
format weeks %tw
}}}

Diff for "Stata/NumericFunctions"