The example i take to be that regress and test could be run repeatedly for different variables. Hello together, is there a command in stata which to search in string variable for a particular word and to return only this word. How do i assign the values of one variable as the value. Suppose that you have numeric data in a variable called x, but because of a mistake, x was made a string variable when you read the data. The program begins by defining the name of the program, i. If the string variable contains anything but numbers, you can add the force option to tell stata to convert it anyway, but observations with any nonnumeric characters will get a missing value. Mar 24, 2020 the data for each day are stored in a separate file, so i wrote a little stata command called covid19 to download, combine, save, and graph these data. A string variable when sorted is necessarily in alphabetic order, or more generally the order given by the string characters used. 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.
Some of these methods assume that the values dont have spaces or symbols that stata wouldnt accept in the variable names otherwise, assign only the variable labels and then see below how to convert labels into names. With a force option, datasets containing numeric variables may also be transposed. An example of when one might need to do this is if they needed to append. The first table lists the number of missing values, as well as percent missing for each variable, this is similar to the table produced by mdesc in part 1 above. The stata blog import covid19 data from johns hopkins. This also influences the results of functions such as strlen. If you copy and paste into the data editor, say, under windows by using the clipboard, but data are spaceseparated, what you regard as separate variables will be combined because the data editor expects comma or. You may also like to learn how to create a string variable in python. Recode the marital variable into a string variable and then back into a numeric variable. String variable definition of string variable by the. Stata module to decode a numeric variable into a string. For example, in the data set below, we have a numeric variable a coded 10 for gender and a string variable b also for gender but with more explicit information. Reed college stata help changing string variables to. Just to add to what pawal stated a few answers prior, once you download the egenmore group, this is an example of the syntax that could work.
I want to a drop a great number of string variables that contain the word other in their observations. The easiest way to convert string variables to numeric form is to use the encode command. As such, i tried the following loop to drop all the variables. Testing for variable type from the capture help file. If a variable is a string, the type will be str followed by some number.
However, the varlist is considered optional, which means that if the user does not. To create dummy variables from variable group, you may use tab group, geng, or use a factor variable, e. Copying data from the internet, csv files, or other sources into stata will record the date as a string variable, shown with red color. The command creates a table that contains the date, the number of confirmed cases, the number of deaths, and the number recovered. In preserving numerical format after string transformation, we used substr to generate a new variable that contains the first 2digits of a numerical code. Sometimes, for whatever reason, stata incorrectly calls a categorical variable a string variable. We have transformed our numeric variable, code, into a string because, as we said, pemdas will not do the trick. Determining if a variable is string or numeric statalist.
How can i quickly convert many string variables to numeric. Quick table for converting different dates to stata format. The variable names correspond to the column names of matrix. How to count total number of string value occurrence per.
If you want to concatenate or combine two string variables in python. Creating and recoding variables stata learning modules. How can i see the number of missing values and patterns of. His problem is how to extract the state, districts, etc. First, use describe to reassure yourself that it is a string.
How can i convert string variables to numeric variables in. Manipulation of string variable using regexm stata. Variable names may be abbreviated to the shortest string of characters that uniquely identifies them. The maximum length of string variables increases from 244 to 2,000,000,000. As strlen refers to the memory used and not the number of characters as they appear on the screen, the result of strlenfur will also be 4 in stata 14 in. How to extract few letters of a string variable in stata.
In stata you can create new variables with generate and you can modify the values of an existing variable with replace and with recode. How can i quickly convert many string variables to numeric variables. Id like to loop through these variables using foreach and perform a recode on the numeric variables. In his case, he has a variable of the form 28180018021832ob where 28 represents state code, 18 represents districts code, 0018 represents subdistricts code and 02183100 represents village code. Apr 12, 2014 in destring complication, anup asked how to split a string variable. Sometimes two variables in a dataset may convey the same information, except one is a numeric variable and the other one is a string variable. The following document provides an example of how to. They take up more memory and are not useful for your regressions, etc. This module shows how to create and recode variables. String variable definition of string variable by the free. The module is made available under terms of the gpl v3.
You can download mdesc from within stata by typing search mdesc see how can i. And, like the pythagorean theorem proofs, there are the very long ones, the shorter ones, and the one that is the most elegant of all. As an example, the german word fur is a string of length three in stata, but the string length is four in stata 14. The data for each day are stored in a separate file, so i wrote a little stata command called covid19 to download, combine, save, and graph these data.
If your strings contain unicode characters or you are writing programs that will be used by others who might use unicode. Possible combination variations of words in a string variable in stata. In the following table, the first column shows different date formats in which the date is already recorded and brought into stata. Different variables have different amounts of missing data and hence, changing. In destring complication, anup asked how to split a string variable. You need to search and install it using findit screening once installed, the syntax you are looking for to obtain a new numeric variable. If the first argument is a string, then all the remaining arguments must be string also. It then alphabetizes that list and assigns numeric codes to each entry.
Encode a string variable nonalphanumerically into a. If you map to a numeric variable, you can use value label definitions to insist on a different order. Therefore you cant destring it and the test for missing would be e. How can i see the number of missing values and patterns of missing.
What command can i use to select variables containing. Assuming sic0 is a one digit numeric variable, you ought to use. This seminar covers stata commands and methods to prepare data for statistical analysis. The first line of syntax reads in the dataset shown above. This module may be installed from within stata by typing ssc install charlist. The easiest way to tell if this is the case is to look at the variables window. Suppose you have a 6digit numeric observation id, code, where the first 2 digits represent geographic code and the last 4 digits represent unique observation codes, and you want to generate a new variable, reg, that represents the 2digit geographic code. The magic here is to convert the string variable sex into a numeric variable called gender with an associated value label, a trick accomplished by encode. Davids example allows you to keep variables according to the variable names, which is a different, but.
A string representing a categorical variable stata. When generating a new variable method 1 1 using nick coxs labgen. In essence, this command is a whitelist command, while a function like subinstr is a blacklist command. Stata module to list characters present in string variable, statistical software components s430301, boston college department of economics, revised 04 mar 2014. We wish to run a regression of high blood pressure on race, sex, and age group. All code for this seminar is available here copy and paste into the stata dofile editor or rightclick to download. In stata, this can be done by using either gen or egen. 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. As in encode, you can and should create a new variable using the gen.
Although the variable science is defined as str2, you can see from the list below that it contains just numeric values. Download these data you will need to unzipextract to use these data files. If the version of the stata instance executing the command is 14 or younger, all unicode contents data labels, variable names, variable labels, value label names and contents, characteristics names and contents are converted to ascii before running saveold. Even so, because the variable is defined as str2, stata cannot perform any kind of numerical analysis of the variable science. I tried determining if the variable was string or numeric by looking at its type.
You should type keep if facilitybir that way, stata knows that bir is a string value. In stata, use the ssc command to do this, or adoupdate if you already. Command generate is used if a new variable is to be added to the data set. The syntax is just destring variable, replace, where variable should be replaced by the name of the variable or variables to be destringed. Create a new variable that associates each individual with the average number of hours worked among individuals with matching educational degrees see the last by example for inspiration. However, this is not elegant because some of the numeric variables are integers, some float etc hence there are different types for different kinds of numerics, and the string variables have different lengths. How to find particular word in string in stata statalist. This package contains two stata programs that are wrappers for java plugins.
There are two cases in which you will want to convert string variables to numeric. The stata website is also a repository for datasets used in the stata manuals and in a number of statistical books. Instead of finding characters that you want to remove, strkeep finds characters that you want to keep and removes all other characters. Conditioning stata dataset on past values of variables. If the variable is actually a numeric value that just happens to be stored as a string, see our faq. Dropping various string variables in a loop in stata. Dropping various string variables in a loop in stata stack. Also, when you ask about a stata program, a stata programmer tends to imagine that you expect to write program and that way to define a new command, but its not at all obvious that you really need to write a new command here. Variables containing stringscalled string variablesoccur in data for a variety of reasons. Stata ships with a number of small datasets, type sysuse dir to get a list.
This module may be installed from within stata by typing ssc install sdecode. However, users of stata versions 12, 11, 10, 9, 8 and 7 can still install the old stata. Before we can use the stata timeseries or paneldata capabilities, we need to convert the string date to a stata date. As example, suppose we have the variables var1, var2, and var3. The default code page of the operating system is assumed as target encoding which. In fact, this finds string variables that are all missing as well. Stata module to replace specific characters or strings in variable names andor variable labels andor string variable values andor value label names and levels with stated charactersstr, statistical software components s4577, boston college department of economics.
To convert them into a stata date, an example code is shown in the second column. This module should be installed from within stata by typing ssc install freqindex. Jan 31, 2020 to create dummy variables from variable group, you may use tab group, geng, or use a factor variable, e. In the display below, sindicates a string subexpression a string literal, a string variable, or another string expression and nindicates a numeric subexpression a number, a numeric variable, or another numeric expression. The first case most often occurs when importing data from another source. Working with variables research guides at bates college. In this section we discuss how to read raw data files. Computing new variables using generate and replace. The program uses stata syntax and expects a variable list and logical expression i. Stata module to generate an index of terms from string variable, statistical software components s457993, boston college department of economics, revised apr 2019. Here is one example where you need to preserve the numerical format for strings. If you type keep if facilitybir then stata will look for a string variable named bir, and will complain if it doesnt find it.
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