It is usually possible to adjust the numeric date or datetime values to the sentinel date and units that stata uses. In stata, this can be done by using either gen or egen. Stata module to decode a numeric variable into a string variable. The first case most often occurs when importing data from another source.
Changing string variables to categorical variables and vice verse. With encode, you need to specify the, generate option and give it a new variable name. A simple way of transforming such a variable to one variable containing the same information is encode. The original answer thus explained why the ops code was wrong, as well as explaining how to do it correctly. Stata can store numbers with differing levels of precision, as described in the table below. For example, criteriabased variable selection in regression analysis can be formalized as. Specifically, l datasets may contain up to 32,766 variables. In stata this is often true because stata treats stringencoded variables as missing. This option can only be used when your input variable is a string, and will be grayed out otherwise. These can be downloaded from two sites, namely from the the statistical software components ssc archive site and from this website. Statase allows stata users to analyze larger datasets. The module is made available under terms of the gpl.
Sometimes, for whatever reason, stata incorrectly calls a categorical variable a string variable. The syntax tostring would only work if tostring were a function, which is not. The easiest way to tell if this is the case is to look at the variables window. Transform string variable to categorical integer variable. If you have more than 67,784 unique values of the string variables that you are encoding, encode will complain. It comes in handy for merging categories, dichotomizing continuous variables and some other tasks. Each morning i have to set my memory size to, say, 20m. Videos you watch may be added to the tvs watch history and influence tv recommendations. In this section i describe stata data files, discuss how to read raw data into stata in free and fixed formats, how to create new variables, how to document a dataset labeling the variables and their values, and how to manage stata system files. The output string variable may either replace the input.
Encode assigns numerical values 1, 2, to newvar, while the original values e. If you have a string variable and you need to generate. 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. Decode for numeric variables statalist the stata forum. Stata noticed that you were setting x1 equal to a string, and thus made x1 a string variable automatically. The first line of syntax reads in the dataset shown above. It then alphabetizes that list and assigns numeric codes to each entry. 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. How to convert a string variable to a numeric variable. These options change the variable type of the new variable. In stata, under the one data principal, any information in the data 11 must be in a variable.
For the love of physics walter lewin may 16, 2011 duration. The concept of string values is explored using the commands tostring and destring and encode and decode. Statistical software components from boston college department of economics. Im trying to import an excel spreadsheet where the variable names are just years. Example 3 we can drastically reduce the size of our dataset by encoding strings and then discarding the underlying string variable. Stata module to encode multiple string variables into numeric, statistical software components s456993, boston college department of economics, revised 21 jan 2009. In cases where a string variable only takes on a small number of values, then converting it into a numeric variable with value labels, using gcollapse, and then recasting the numeric converted variable back into a string works just fine e. Spss recode replaces data values with different values. Stata news, code tips and tricks, questions, and discussion. To concatenate is to join the characters of 2 or more variables from end to end. To be able to perform any mathematical operations, your variables need to be in a numeric format. How can i quickly convert many string variables to numeric variables. Is there a way to tell stata to try all values of a particular variable in a foreach statement without specifying them.
Stata is agile and easy to use, automate, and extend, helping you perform data manipulation, visualization, and modeling for extremely large data sets. If for some reason you want to convert a numeric variable into a string variable, you may use the complementary function decode. I suspect stata does not handle decimal labels well, which my data set contains a lot of. Title syntax menu description options for encode stata. The following document provides an example of how to. Unlike decode, sdecode creates an output string variable containing the values of the input variable as output by the list command and other stata output, instead of decoding all unlabelled input values to missing. A user who wants the latest version of a package should download from ssc, if the users version of stata is ccompatible with the latest version of the package. If you really want a string variable, you need decode, not tostring. Cialis 40 mg, cialis price rprogramming online pill. We have a string variable, sex, that records each persons sex as male and female. If the variable is actually a numeric value that just happens to be stored as a string, see our faq. As before,s may be a literal string or the name of a string variable, but is most commonly the latter.
Optionally, the user may specify a list of string header rows to be output before the observation rows. Learn how to change string variables into numeric variables and numeric variables into string variables in stata. There may be times that you receive a file that has many or all of the variables defined as strings, that is. It sometimes happens that you need to process in stata data imported from other software and end up with a numerical variable recording a date or datetime in the other software s encoding. String variables can have varying lengths up to 244 characters in stata 12, or up. How can i convert string variables to numeric variables in. Stata module to decode a numeric variable into a string. Statase is ready and we think you are going to like it. Here we use the generate command to create a new variable representing population younger than 18 years.
Generating composite categorical variables nicholas j. Odd numbers of characters in string variables were soon allowed in stata 2. Not surprisingly, stata requires the numeric variable to be labeled. The name hidden variables may be slightly more dramatic than need be. Example of turning string variables into numeric variables are shown. This post demonstrates how to create new variables, recode existing variables and label variables and values of variables. The opposite of encode is decode the decode command has the same. As example, suppose we have the variables var1, var2, and var3. In this course, franz buscha provides a comprehensive introduction to stata and its various uses in modern data analysis. With destring, you need to specify either the, generate option or the, replace option.
Is there some way to differentiate between value labels for an actual numeric variable and one for a string variable weight vs. If a variable is a string, the type will be str followed by some number. Software like stata, an integrated statistical software package, can help. The second point may suggest using decode instead, but my suggestions di. If playback doesnt begin shortly, try restarting your device. How can i quickly convert many string variables to numeric. The table is derived by outputting the values of these variables, preceded by a begin string option, separated by a delimiter string option, and su. Although the variable science is defined as str2, you can see from the list below that it contains just numeric values. Befehl abbricht, wenn beim erzeugen einer string variable ein fehler.
The output string variable may either replace the input numeric variable or be generated as a new variable named newvar. If you have a string variable and want to convert it to a numeric variable. Here, and indeed elsewhere, it helps to think of numeric missing as arbitrarily large. The easiest way to convert string variables to numeric form is to use the encode command. Even so, because the variable is defined as str2, stata cannot perform any kind of numerical analysis of the variable science. This module should be installed from within stata by typing ssc install multencode. The download facility on this website is mainly provided for.
Subsequently, each variable can be stored in a number of storage types byte, int, long. When cleaning datasets one often has string variables containing categories e. This only works if your original string variable is spelled consistently. Press question mark to learn the rest of the keyboard shortcuts. You can only tell the type of a variable by using the describe command. We are here to help, but wont do your homework or help you pirate software. Reed college stata help changing string variables to.
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