help contract dialog: contract
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Title
[D] contract -- Make dataset of frequencies and percentages
Syntax
contract varlist [if] [in] [weight] [, options]
options description
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Options
freq(newvar) name of frequency variable; default is _freq
cfreq(newvar) create cumulative frequency variable
percent(newvar) create percentage variable
cpercent(newvar) create cumulative percentage variable
float generate percentage variables as type float
format(format) display format for new percentage variables;
default is format(%8.2f)
zero include combinations with frequency zero
nomiss drop observations with missing values
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fweights are allowed; see weight.
Menu
Data > Create or change data > Other variable-transformation commands >
Make dataset of frequencies
Description
contract replaces the dataset in memory with a new dataset consisting of
all combinations of varlist that exist in the data and a new variable
that contains the frequency of each combination.
Options
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----+ Options +----------------------------------------------------------
freq(newvar) specifies a name for the frequency variable. If not
specified, _freq is used.
cfreq(newvar) specifies a name for the cumulative frequency variable. If
not specified, no cumulative frequency variable is created.
percent(newvar) specifies a name for the percentage variable. If not
specified, no percent variable is created.
cpercent(newvar) specifies a name for the cumulative percentage variable.
If not specified, no cumulative percentage variable is created.
float specifies that the percentage variables specified by percent() and
cpercent() will be generated as variables of type float. If float is
not specified, these variables will be generated as variables of type
double. All generated variables are compressed to the smallest
storage type possible without loss of precision; see [D] compress.
format(format) specifies a display format for the generated percentage
variables specified by percent() and cpercent(). If format() is not
specified, these variables will have the display format %8.2f.
zero specifies that combinations with frequency zero be included.
nomiss specifies that observations with missing values on any variable in
varlist be dropped. If nomiss is not specified, all observations
possible are used.
Examples
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Setup
. sysuse auto
Replace dataset with dataset containing all combinations of foreign and
rep78 along with the frequency with which each combination occurs
. contract foreign rep78
List the result
. list
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Setup
. sysuse auto, clear
Same as above, but include combinations that have 0 frequency
. contract foreign rep78, zero
List the result
. list
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Setup
. sysuse auto, clear
Same as above, but name frequency variable count
. contract foreign rep78, zero freq(count)
List the result
. list
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Setup
. sysuse auto, clear
Same as above, but drop observations with missing values
. contract foreign rep78, zero freq(count) nomiss
List the result
. list
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Setup
. sysuse auto, clear
Include cumulative frequency variable in dataset
. contract foreign rep78, cfreq(cumfreq)
List the result
. list
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Setup
. sysuse auto, clear
Same as above, but also include a percentage variable and cumulative
percentage variable in dataset
. contract foreign rep78, cfreq(cumfreq) percent(percentage)
cpercent(cumpercent)
List the result
. list, abbrev(10)
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Also see
Manual: [D] contract
Help: [D] collapse, [D] duplicates, [D] expand
