If what to you are strings that mean the same are in fact different, e. If a variable is a string, the type will be str followed by some number. Sometimes, for whatever reason, stata incorrectly calls a categorical variable a string variable. Our one to one merge matched up dads and faminc and there was a one to one matching of the files. Read each dataset into stata and sort it by the merging variable ex.
How can i quickly convert many string variables to numeric. Variable data software solution for variable data printing and variable data publishing, vdp software designmerge is an addon component for the desktop publishing applications, quarkxpress and adobe indesign, which allows users to create customized 1. In addition, i advise verifying the leading characters, particularly in the. In stata, this can be done by using either gen or egen. The following document provides an example of how to create string variables from numeric variables, and then concatenate string variables into one. If i first encode the string variable in one data set and then do the same in another data set, i end up with two variables that have been encoded differently. Combining datasets in stata thomas elliott january 31, 20 often, you will nd yourself with two or more datasets, or data les, that you wish to combine into one data le. The following document provides an example of how to. An example of when one might need to do this is if they needed to append several variable sets together, and they needed a unique identifier the included information about the source data set.
Sep 27, 2016 this feature is not available right now. Stata is a complete, integrated software package that provides all your data science needsdata manipulation, visualization, statistics, and automated reporting. Following this entry,d data management provides an overview of data management in stata and of statas data management commands. Merging two datasets require that both have at least one variable in common either string or. Reed college stata help changing string variables to. This can happen to both string and numeric variables, but right now, we are going to emphasize the numeric case. Data manipulation and analysis it services 2 note the. To be able to perform any mathematical operations, your variables need to be in a numeric format. Stata module to concatenate variables into string variable. That intended purpose does not stop tostring being useful for things for which it. When i add the variable to the dataset, stata recognizes it as a string variable.
You can just leave those variables in your datasets when you merge them together, however, there are several reasons you might not want to do this. The first line of syntax reads in the dataset shown above. The easiest way to tell if this is the case is to look at the variables window. Hello, i am having a difficult time trying to figure out how to merge the two different variables into one variable. Command generate is used if a new variable is to be added to the data set. Merge datasets by partially matching key variables in stata i work with messy administrative data and very often have to merge datasets by peoples or cities names.
How shapeways software enables 3d printing at scale. The properties window gives us the same information as the above. May 07, 2016 merge datasets by partially matching key variables in stata i work with messy administrative data and very often have to merge datasets by peoples or cities names. Datetime data analysis with stata library guides at. To create the two dataset, we can copy and paste the following code to stata do editor and run it. With stata 16 you can store both datasets as frames, and link the household data to each individual. This module will illustrate how you can combine files in stata. How to download, import, and merge multiple datasets from the nhanes website how to download, import, and prepare data from.
The variable does not contain nonnumeric characters. Merging string variables statalist the stata forum. This will likely happen again and again, and again. In previous versions of stata you would have had to merge the files. On april 23, 2014, statalist moved from an email list to a forum.
How to recode string variables with multiple values in one cell in spss. Matching on groups as well as on the nearest value of a. Sort by key variables first, and then enter the merge command, making sure the data set with the many observations is the current data set in memory for m. Make sure to map where the using data is located in this case mydata2, for example c. In many cases you can avoid managing multiply imputed data completely.
Merge datasets by partially matching key variables in stata. At least a common variable based on which we will merge. Where there is no alter, or where alters id is not present in the data as an egorecord, the index variable will be missing. Stata calls it merging when observations from the two data sets are combined. Before you can merge data in stata, you must do two things. In order for stata to merge the datasets, the id variable, or variables, will have to have the same name across all files. Stata can store numbers with differing levels of precision, as described in the table below. To merge a using file with a master file, they must have. Consider a situation where you have household and individual data on separate files, both with a common household id, and need to combine them. First use the command trim for your strings before you merge datasets. Sort by key variable s first, and then enter the merge command, making sure the data set with the many observations is the current data set in memory for m. Oct 05, 2010 to concatenate is to join the characters of 2 or more variables from end to end. Spsspasw will allow you to save your data as a stata file. Hot network questions two year old son sometimes using female verb endings grammar issue.
Copy the following code and run from stata do editor. Alasi guess i am stuck with converting ids to string for the merge. Combining data sets this is part eight of the stata for researchers series. Nevertheless, to do this, if i am not mistaken, previously i have to combine these two identifying variables to generate, eg, values such as. A merge basically connects rows in two datasets stata calls them observations based on a specified variable or list of variables, called key variables. To create new variables typically from other variables in your data set, plus some arithmetic or logical expressions, or to modify variables that already exist in your data set, stata provides two versions of basically the same procedures.
Merging and appending stata research guides at bates. Any string in var that does not meet the conditions of rules is set to missing in created numeric variables and copied from var in created string variables. Merge with the faminc2 file using famid as the key variable. I may post updates in the future as the data change, but you may need to adapt sooner than i. Stata module to recode string variables according to. Splitting a string variable in stata, and placing values in order.
Spss has spss analytic server, spss modeler, spss statistics and different variable types such as string and numeric and has different variable formats whereas stata has different word documents to be created to automate the reports and generate results and graphs in. You have to start with one dataset already in memory stata calls this the master dataset, and you merge another dataset to it the other dataset is called the using dataset. It is a program written by michael blasnik to merge imperfect string variables. As you see below, the strategy for the one to many merge is really the same as the one to one. Var2 is a string variable even though you see numbers. You might also want to read bill goulds excellent blog entry, discussing potenial problems with merge. If string make sure the categories have the same spelling i. Watch out for leading and trailing spaces, inconsistencies of case and other spelling differences. Additionally, if the variable is a string in one dataset, it must also be a string in all other datasets, and the same is true of numeric variables the specific storage type is not important, as long as they are numerical. First, there is a limit on the number of variables stata can handle.
Merging and appending stata research guides at bates college. Stata module to provide nearestmatch merging of datasets. How to extract few letters of a string variable in stata. Introduction to stata generating variables using the generate, replace, and label commands duration. Make sure one dataset is loaded into stata in this case mydata1, then use merge. To recap, the sort of data this is intended for includes records for both ego and alter, keyed on an id variable, and linked by a variable that contains alters id. If youre new to stata we highly recommend reading the articles in order. The other parts of this manual are arranged alphabetically. As example, suppose we have the variables var1, var2, and var3. May 23, 2017 for the love of physics walter lewin may 16, 2011 duration. If we are inputting string character variables, precede the string variable. If we merge dads with kids, there can be multiple kids per dad and hence this is a one to many merge. Benini 2008 presented solutions, in excel as well as stata, for table merging when the link variables are text based with spelling differences. To merge these two data sets, follow the appropriate instructions below.
Combining two data sets is a common data management task, and one thats very easy to carry out. I wrote that on march 19, 2020, and the data changed on march 23, 2020. Your are right there still were trailing blanks in the strings i didnt. Variables may either be recoded into numeric variables or into string variables. You can merge on string variables directly and that is the advised procedure if string variables are identifiers for your dataset. No matter what type of data you are merging cross section or panel data or time series you need some type of identifier variable in both fi. In data management, sets of information may have to be linked for which the common link variables agree only partially. To concatenate is to join the characters of 2 or more variables from end to end. Think about languages that use diacritical marks and you have a complete mess.
In small stata the limit is 99, in stata ic the limit is 2,047 and in statase and stata mp. String identifiers as such are not problematic, but note that matches must be exact as with numeric identifiers. Another kind of merge is called a one to many merge. Can i successfully merge the datasets with the variable still in string format. Create a date variable from a date stored as a string optimize the storage of variables round a continuous variable stata s expression builder examining data identify and remove duplicate observations labeling, display formats, and notes label variables label the values of categorical variables change the display format of a variable add notes. To merge two data sets in stata, first sort each data set on the key variables upon which the merging will be based. Value labels will be defined for numeric variables. Wherever possible, do any needed data cleaning, recoding, restructuring, variable creation, or other data management tasks before imputing. If a variable only appears in one data set, observations from the other data set.
You cant do any statistical procedure with this variable other than. The results window tells us that day is of type str9 a string thats 9 characters in length. Spss has spss analytic server, spss modeler, spss statistics and different variable types such as string and numeric and has different variable formats whereas stata has different word documents to be created to automate the reports and generate results and graphs in tabular and text formats. If you are new to statas data management features, we recommend that you read the following. I am going to assume you are familiar with statas merge command. If you map to a numeric variable, you can use value label definitions to insist on a different order. One method of converting numbers stored as strings into numerical variables is to use a string function called real that translates numeric values stored as strings into numeric values stata can recognize as such. The variable must be in the same format in both the master file and the using file. Merge two data sets in the manytoone relationship in stata. I would like to merge two data sets that have in common string variables.
String variables often come with typos, different spelling, etc. If you are writing a stata program that temporarily changes the dataset by the. Apr 14, 2020 the date variable, day, is a string variable. Merging two datasets require that both have at least one variable in common either string or numeric. For a list of topics covered by this series, see the introduction.
A string variable when sorted is necessarily in alphabetic order, or more generally the order given by the string characters used. This is part five of the multiple imputation in stata series. Handling dyadic data in stata sociology, statistics and. Note that the difference between numeric and string in stata is one of datatype, not format. Combining datasets using stata is a frequent task in data analysis. How to recode string variables with multiple values in one. My merge no longer works properly, because the numerically assigned labels are different. If they are in string alphanumeric format in the both the files, their spelling must be same i. Hello, im working with string variables in spss and encountered a problem in managing the data. What if my data is from another statistical software program. Merging datasets in stata on long strings and less precise. Spss vs stata top 7 useful differences you need to know. Examples will include appending files, one to one match merging, and one to many match merging.