Stata file write append

We tell Stata to read a line from the file we have called myfile by starting with the command file read myfile and then giving Stata the name of the local macro where we want Stata to store the information from the file, in this case, line. The second line of code uses the!

You have to specify the name of the file in our example it is called myfilebecause it is possible to have more than one file open at a time, meaning that we need some way to tell Stata which file we are referring to with any given command.

It will continue to do this until it runs out of observations in one data set or the other. The unique identifier of the students ID is irrelevant in this case because the merge is performed using the household identifier HH.

How can I append (stack) a large number of files? | Stata FAQ

You can do this from within Stata, since Stata is capable of relaying commands to your operating system. No, these notes do not indicate a problem with the append. Remember that the merge command requires both datasets to be sorted by the identifying variable we want to use to merge before the launch of the command.

Note that we do not want to place the file filelist.


They mean that the file in memory has label definitions with the same names as those in the "using" file on disk. When using append, the two files should have identical variable names.

Combining data | Stata Learning Modules

On the contrary, if there are more variables in the Using data than in the Master data, the observations from the Master Dataset will present missing values in them. Adding Variables The horizontal combination, known as merging procedure, is useful when we want to add variables instead of observations.

Several notes appear in the Stata log about labels already being defined. Is this a problem? Many-to-many merge This merging method is extremely rare and difficult to perform. I will come back on loop and macros in a new post!

Appending data files

Well, yes, but we have to take care of something precautionary. The second line of syntax below reads the next line in myfile.

Merge and Append: Datasets Creation Tools

The next argument is the place in the string where we want to start extracting information, in this case, we want to start with the 9th character in the string. I will present here both the old version of the command still useable and the new one.

We know that when we use the file read command, Stata reads lines one a time, and that each time we ask it to read a line, Stata reads the next line in the file. As long as we are not at the end of the file, r eof is equal to zero, when the end of the file is reached, Stata sets r eof equal to one, and the local macro specified in the command in our case line will be empty.

If we have an identifying variable in both files i. Because sometimes data come from different sources that we need to aggregate.

We will show how to combine files already in Stata format, and how to perform the same task with datasets that come as text files. The first step is to create a list of files that need to be read in.

Before we begin, it is useful to know a few things about the commands we will be using.

In Stata, how do I save outputs in an external file?

The first line of syntax below moves us to the directory where all of the files we want to merge are stored. For example, you have data on cars and their models and prices in in the dataset auto. As we do this, we will also add a variable which identifies which dataset the file came from.

The answer is straightforward, Yes. Copy these commands into a do-file editor and run them. You can also omit to declare stata file write append data is a.

You only must be sure that all the datasets you want to merge are in the same directory and are coded similarly.Mar 04,  · for more information on how to append datasets, open stata and type in 'help append' you can also check out: if "`f'" ~= "`firstfile'" append using `f'.

} - -- Ulrich's solution works, but I thought it was worth pointing out another approach: clear fs *.dta local getfile "use" foreach file in `r(files)' { `getfile' `file' local getfile "append using " } I often use local macros in this way, where a different command, or option, is needed at different stages in a loop.

I have a situation where I need to import all the files in a directory and append them. My code is this local files: dir "C:\Users\xx" files "*.xls" local n: word count `files' tokenize ``files. This add the observation from the file autonew to the data in memory in auto.

You can also omit to declare your data is, Stata recognizes this format by default. I always recommend you to save different files when you manage the data to prepare your final dataset, in order to avoid overwriting, as already said in this post.

The text option above writes the log file in ASCII format; the default is the SMCL (Stata Markup and Control Language) format. The replace option overwrites an existing file. To append the log file, use append instead. After the append command, the resulting file should also have that number of variables.

If the files have the same number before but one more variable after the append, you know that a variable in one of the input files had a different name.

Stata file write append
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