help language
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Title
[U] 11 Language syntax
Syntax
With few exceptions, the basic language syntax is
[prefix :] command [varlist] [=exp] [if] [in] [weight]
[using filename] [, options]
see language element description
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help prefix prefix : prefix command
help command command Stata command
help varlist varlist variable list
help exp =exp expression
help if if if exp qualifier
help in in in range qualifier
help weight weight weight
help using using filename using filename modifier
help options options options
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Description
Stata commands follow a common syntax. A command's syntax diagram shows
how to type the command, indicates possible options, and gives the
minimum allowed abbreviations for items in the command.
Remarks
In a syntax diagram, square brackets distinguish optional from required
options. Items presented like this should be typed exactly as they
appear in the diagram. Underlining is used to indicate the shortest
abbreviations where abbreviations are allowed, so that an item presented
like this indicates that this may be abbreviated to th. Items presented
like this represent arguments for which you are to substitute variable
names, observation numbers, and the like.
Options, denoted as options in the generic syntax diagram above, are
specified at the end of the command. A comma must precede the first
option.
Some options take numeric lists as arguments. See help numlist for
details on various ways of specifying these numeric lists.
Some commands also have an immediate form (allow you to enter numbers
directly instead of entering variable names). See help immed for
details.
Programmers interested in incorporating Stata's language features into
their Stata programs should see help syntax for the syntax command.
Examples
count command
The count command has the following syntax diagram:
count [if] [in]
count is the command and it may be abbreviated to cou. The if and in
qualifiers are optional; see help if and help in.
Examples:
. sysuse auto
. count if rep78 > 4
. count if weight < 3000
. cou if rep78 > 4 & weight < 3000
replace command
The replace command has the following syntax diagram:
replace oldvar =exp [if] [in] [, nopromote ]
replace is the command. oldvar corresponds to varlist in the generic
syntax diagram. Here oldvar is required because there are no square
brackets around it. The equal sign followed by an expression is also
required. The if and in qualifiers are optional. There is one
option, nopromote, which may be abbreviated to nop. If this option
is specified, it must follow a comma after the earlier parts of the
command have been typed.
Examples:
. sysuse nlsw88
. replace married = 2 if never_married == 0 & married == 0
. replace wage = wage * 2080
. replace age = age^2, nopromote
Also see
Manual: [U] 11 Language syntax
