Merging two datasets require that both have at least one variable in common either string or numeric. For xtsetting youll also need a numeric variable, but i find it best to create a new variable for that purpose, either a copied and then encoded id variable, or using egen group. Even so, because the variable is defined as str2, stata cannot perform any kind of numerical analysis of the variable science. If you wish to add new observations to existing variables, then seed append. You may also like to learn how to create a string variable in python. String variables often come with typos, different spelling, etc. I seem to be able to use a string variable for that too so i suppose statas merge behavior is alright in the end.
On april 23, 2014, statalist moved from an email list to a forum, based at. Stata module to concatenate variables into string variable. Output statas ttest results with esttab including means of each group. Combining datasets using stata is a frequent task in data analysis. Encoding is useful for dummy variables or variables that categorize observations in a limited number of groups. In this blog post, we show how to merge two dataset on a criterion variable that is. Although the variable science is defined as str2, you can see from the list below that it contains just numeric values. The sites i have seen also mention a pvar package that you have to download but i cant seem to find it. 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.
A stata dataset is a rectangular arrangement of values, where rows are observations columns are variables 4 clear all describe the current stata dataset in memory master dataset describe create some observations still no variables set obs 5 create a variable named x, which has the. 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. Variables may either be recoded into numeric variables or into string variables. In data management, sets of information may have to be linked for which the common link. Programming with stata abdul latif jameel poverty action lab. Note that the difference between numeric and string in stata is one of datatype, not format. In merging data, part 1, i discussed singlekey merges such as. I have looked how to do this on stata which we normally use in my uni but everything seems very convoluted even though im only doing a 2 variable regression. I have 970 obs in one variable and 270 obs in the other variable. Merge datasets by partially matching key variables in stata.
In order for stata to merge the datasets, the id variable, or variables, will have to have the same name across all files. Merging datasets in stata on long strings and less precise matching criterion. You have to start with one dataset already in memory stata calls this the master dataset, and you merge another dataset to it. Therefore i would like to generate a variable combining two string variables origin and. As you can see from the second tabulate, region2 has the numeric values 1 through 4 but retains the strings central, east, south and west as value labels. To concatenate is to join the characters of 2 or more variables from end to end. 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. Another dataset containing doctor variables will be merged into this. You merge when you want to add more variables to an existing dataset type help merge in the.
If you want to concatenate or combine two string variables in python. Value labels will be defined for numeric variables. If we are inputting string character variables, precede the string variable. Merging datasets in stata on long strings and less precise matching. 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. Start by opening the master dataset, in this case the menwomen dataset that we just saved.
These string variables can be used in creating row labels for output tables andor plots, possibly using the sencode package. I want the new, combined, single variable to have all 1240 obs while retaining their original values. A sequential merge performs a onetoone merge on observation number. Johannes if the second variable is a string, you can concatenate it. Think about languages that use diacritical marks and you have a complete mess. The good news is that i was especially avoiding this solution because i had assumed that i couldnt then use a string id var as an identifier in statas xtmixed or other xt routines, so i had to backconvert into a numberic id. How can i convert string variables to numeric variables in. If string make sure the categories have the same spelling i. If what to you are strings that mean the same are in fact different, e.
After the merge statement, we must specify the type of merge 1. Merging string variables statalist the stata forum. The first line of syntax reads in the dataset shown above. In that discussion, each observation in the dataset could be. This can be useful to add data that may not be used in the ensuing statistical analysis, such as graphing data. You use append, for instance, when adding current discharges to past discharges. You can merge on string variables directly and that is the advised procedure if string variables are identifiers for your dataset. If the key variable has variations in terms of capitalization and number of characters. I would also add the ignore option just in case it complains about commas being nonnumeric. The observations are matched based on specified variables. The name variable is the key variable that we are using as the merging criterion. Matching on groups as well as on the nearest value of a.
Stata allows data to be entered directly through the keyboard with the input command, even when another dataset is already in memory. Spsspasw will allow you to save your data as a stata file. The first tabulate looks identical to the tabulate done on the string variable region above. How can i quickly convert many string variables to numeric. How to import excel file with multiple sheets into stata. Would anybody be able to download it for me and convert it to an excel.
Introduction to stata generating variables using the generate, replace, and label commands duration. I would try method 3, but generate a new variable to see where exactly stata thinks there are missing values and add the force option. Matching on groups as well as on the nearest value of a numeric variable, in ms excel and in stata. I want to merge several datasets but their id variable is a string variable. In case the stata manual is unclear, heres a quick overview first, its important to clear up the terminology. Multiplekey merges arise when more than one variable is required to uniquely identify the observations in your data. In this short video i explain how to combine stata data files and why you would ever want to do such a thing. 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. Since it is a user created program, you may need to install it by typing. Gvkey is numeric in your first data set, but character in your second data set.
Neil one should as a rule, respect public opinion in so far as is necessary to avoid starvation and to keep out of prison. By default, stata performs an outer join, where all observations from both data sets are left in memory after the merge. By default, merge creates a new variable, merge, containing numeric codes concerning the source. Specifically, i show how to use statas append and merge commands.
Another option is stattransfer, a program that converts data fromto many common formats, including sas, spss, stata, and many more. To merge two data sets in stata, first sort each data set on the key variables upon which the merging will be based. Whats different with the new syntax what are its valueadded. A merge basically connects rows in two datasets stata calls them observations based on a specified variable or list of variables, called key variables. It is a program written by michael blasnik to merge imperfect string variables. And option higher 30 and lower 10 sets the limits for sub string extraction for creating the truncated variables that will be used for merging.