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help reshape dialog: reshape
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Title
[D] reshape -- Convert data from wide to long form and vice versa
Syntax
Basic Syntax
reshape long stubnames, i(varlist) [options]
reshape wide stubnames, i(varlist) [options]
reshape error
long
+------------+ wide
| i j stub | +----------------+
|------------| | i stub1 stub2 |
| 1 1 4.1 | reshape |----------------|
| 1 2 4.5 | <---------> | 1 4.1 4.5 |
| 2 1 3.3 | | 2 3.3 3.0 |
| 2 2 3.0 | +----------------+
+------------+
To go from long to wide:
j existing variable
/
reshape wide stub, i(i) j(j)
To go from wide to long:
reshape long stub, i(i) j(j)
\
j new variable
To go back to long after using reshape wide:
reshape long
To go back to wide after using reshape long:
reshape wide
options description
-----------------------------------------------------------------------------------------------------------
* i(varlist) use varlist as the ID variables
j(varname [values]) long->wide: varname, existing variable
wide->long: varname, new variable
optionally specify values to subset varname
string varname is a string variable (default is numeric)
-----------------------------------------------------------------------------------------------------------
* i(varlist) is required.
where values is #[-#] [...] if varname is numeric
(default)
"string" ["string" ...] if varname is string
and where stubnames are variable names (long->wide), or stubs of variable names (wide->long), and either
way, may contain @, denoting where j appears or is to appear in the name.
In the example above, when we wrote "reshape wide stub", we could have written "reshape wide stub@"
because j by default ends up as a suffix. Had we written stu@b, then the wide variables would have been
named stu1b and stu2b.
Advanced syntax
reshape i varlist
reshape j varname [values] [, string]
reshape xij fvarnames [, atwl(chars)]
reshape xi [varlist]
reshape [query]
reshape clear
Menu
Data > Create or change data > Other variable-transformation commands > Convert data between wide and long
Description
reshape converts data from wide to long form and vice versa.
Options
i(varlist) specifies the variables whose unique values denote a logical observation. i() is required.
j(varname [values]) specifies the variable whose unique values denote a subobservation. values lists the
unique values to be used from varname, which typically are not explicitly stated because reshape will
determine them automatically from the data.
string specifies that j() may contain string values.
atwl(chars), available only with the advanced syntax and not shown in the dialog box, specifies that chars
be substituted for the @ character when converting the data from wide to long form.
Remarks
Before using reshape, you need to determine whether the data are in long or wide form. You also must
determine the logical observation (i) and the subobservation (j) by which to organize the data. Suppose
that you had the following data, which could be organized in wide or long form as follows:
(wide form)
i ....... x_ij ........
id sex inc80 inc81 inc82
-------------------------------
1 0 5000 5500 6000
2 1 2000 2200 3300
3 0 3000 2000 1000
(long form)
i j x_ij
id year sex inc
-----------------------
1 80 0 5000
1 81 0 5500
1 82 0 6000
2 80 1 2000
2 81 1 2200
2 82 1 3300
3 80 0 3000
3 81 0 2000
3 82 0 1000
Given these data, you could use reshape to convert from one form to the other:
. reshape long inc, i(id) j(year) (goes from top form to bottom)
. reshape wide inc, i(id) j(year) (goes from bottom form to top)
See [D] reshape for a detailed discussion and examples for both the basic and advanced syntax.
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