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The IPA high intermediate Stata training also has a helpful module on merging, including a discussion of common pitfalls.R r RSS Feed channeldata.json linux-32 linux-64 linux-aarch64 linux-armv6l linux-armv7l linux-ppc64le linux-s390x noarch osx-64 osx-arm64 win-32 win-64 zos-z PackageĪ mutex package to ensure environment exclusivity between Anaconda R and MRO.Ĭombine multidimensional arrays into a single array.
Geodist stata two datasets how to#
See the IPA Stata beginner’s training manual for step-by-step guidance on how to merge datasets. If you are not familiar with any of these see the help merge file. Options that are helpful to include are assert, keep, keepusing, gen, nogen. You should look at the documentation for both safemerge and mmerge for alternative merge methods. There are a couple other merge command options that try to build in more safety features for you. Adding a few assertions after the merge is good practice to make sure things are running correctly. After the merge, type tab _merge and check to see that the results (number of matches, number from master data only, number from using data only, updated missing values, and conflicting nonmissing values) were what you expected. In a merge, each type of “match” is assigned a number (see help merge for the numeric codes assigned). So it matches the first observation in dataset 1 for person 1 with the first observation in dataset 2 for person 1 and so on. Rather, a many-to-many merge pairs your two datasets by the way the observations are sorted within the id. If this is what you desire you should use joinby. Many people think that a many-to-many merge will create all of the pairwise combinations of observations that match on each ID. Many-to-many mergeĪ many-to-many merge is a really bad practice and should not be done. However, it probably makes more sense to rename one of the variables and keep both.
Geodist stata two datasets update#
You can change this assumption by using the update and/or replace options to use the using values. When you perform a merge, if you have the same variable in both datasets, Stata will automatically keep the master data as authority. You should also check that your two datasets do not have any variables with the same names. Be sure that both datasets have a unique ID and be extra careful to specify whether the merge is one-to-one or one-to-many (although you will receive an error if you do the wrong merge type so you don’t have to worry too much about this causes problems). For example, you may have variables that were split between two datasets by the survey program. You may also need to merge two or more datasets together, if they are split by variables and contain the same observations.