Cox and newton 2014 provide a detailed description of indispensable tools for dealing with lists and macros. Stata news, code tips and tricks, questions, and discussion. How to create a date variable from a date stored as a string. Converting dates entered as strings into numeric dates that can be used by stata is relatively simple. Inputting your data into stata stata learning modules. In most cases, stata can handle dates in which the days were entered as one or two digit numbers, and in which the month was entered as either abbreviation e. In stata, this can be done by using either gen or egen. You can only tell the type of a variable by using the describe command. I have a data set given to me in an excel spreadsheet that i have imported into stata 467 observations, 2 variables. How to extract few letters of a string variable in stata. Counting nonmissing observations by variable statalist. Stata is not sold in modules, which means you get everything you need in one package. Oct 05, 2010 to concatenate is to join the characters of 2 or more variables from end to end. I here create a dataset with all the crosscombinations needed and also create a variable with explicit zeros to show.
We will show some examples of how to use regular expression to extract andor replace a portion of a string variable using these three functions. Fortunately, stata offers some easy ways for converting string to numeric variables and vice versa. Instructor franz buscha explores advanced and specialized topics in stata, from panel data modeling to interaction effects in regression. I want to use a loop to import and save these files. The stata blog import covid19 data from johns hopkins. Although it seems like region is a string variable, it is really a numeric variable with an attached value label. Since make is a character variable, we need to tell stata that it is a character variable, and how long it can be. The first line of syntax reads in the dataset shown above. How can i quickly convert many string variables to numeric. Learn how to use the date function with this stata quick tip from chuck huber. That will give you a list of values that stata did not destring and you can make the changes to the new variable as needed. When coding these steps in stata, users nd that stata does not allow string values in matrices. You could get stata to display it as a date by entering format %td statadate. Reshape data in stata an easy to understand tutorial.
I have three id variables in string format with missing observations. Stata 11 introduced a variables manager that allows editing variable names, labels, types, formats, and notes, as well as value labels, using an intuitive graphical user interface available under datavariables manager in the menu system. How to convert categorical string variables to labeled numeric variables. Help with changing variable format 15 jul 2015, 12.
This conversion can be done using the string function with an option for the format. To truly use this data for a time series or panel data analysis, you would need to format month as a date. Stata 11 introduced a variables manager that allows editing variable names, labels, types, formats. Nearly all the variables contain numeric values, but they are all read by stata as string variables because whoever entered the data into excel included % symbols. In spss versions 24 and higher, tiny icons in front of variable names tell us the variable type, format and even measurement level.
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. My problem is that when i convert my product codes which are string variables into numeric, stata inputs the numeric code as chronological numbers, and this is why the scale of my x axis no longer reflects the scale of my original string variable. Jan 05, 2011 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. While the manager is certainly convenient, i still prefer writing all commands in a do file to ensure. I tried using help export, and i only see references for exporting into excel or text files and nothing about exporting into separate stata data files. Before we can use the stata timeseries or paneldata capabilities, we need to convert the string date to a stata date. Once you have read this post, then you can read another post that lists a quick table of dates conversions from one frequency to another. How can i turn a string variable containing dates into a date.
Datestringvar, date format so here string var is the variable name, and date format it where you tell stata how the date is formatted, so in your second dataset it would be day, month, year so you would put dmy with quotes as the. Among these string functions are three functions that are related to regular expressions, regexm for matching, regexr for replacing and regexs for subexpressions. Similar rules exist for changing the way the date and. For converting metric string variables holding just numbers into numeric variables, see spss convert string to numeric variable.
I know i can use the insheet command to actually import the files into stata, but i do not see how to save each of these files into stata format through the program. Often when importing data, stata can mistake a numeric variable for a string variable. Display all levels of a variable while tabulating in stata. Since we need to convert the data from a wide format to a long format, this is why the command that we wrote was reshape long. The easiest way to tell if this is the case is to look at the variables window. I am trying to import multiple files in csv format into stata. Here is one example where you need to preserve the numerical format for strings.
As example, suppose we have the variables var1, var2, and var3. In this course, take a deeper dive into the popular statistics software. Press question mark to learn the rest of the keyboard shortcuts. Graph with a string variable statalist the stata forum. Stata module to leftalign or right align variables, statistical software components. The put function can also be used to convert a character variable to another character variable, with a character format. Var2 is a string variable even though you see numbers. Stata s no metaphysician and is reluctant to display anything without empirical evidence to hand that it exists. If you have more than 67,784 unique values of the string variables that you are encoding, encode will complain.
Data preparationdescriptive statistics princeton university. In this post, i would like to show how to convert a numeric date to stata date. In sas, we will create a format from the string variable and apply the format to the numeric variable. The stata blog using dates and times from other software. The commands vary somewhat based on the format in which the data were entered and how consistently that format was applied. If you browse the data now youll see that statadate is simply a number. Say that we have date variable in the following format and we want to convert it to stata format. How can i extract a portion of a string variable using.
If a variable is a string, the type will be str followed by some number. Changing string variables to categorical variables and vice verse. The entries in variable code, with numeric format %06. Reed college stata help changing string variables to. So format %10s state would cause stata to display the variable called state, aligned to the left with the first 10 characters displayed dates. The str tells stata it is a string variable and that it could be up to characters wide. But no one wants to scroll through what may be screenfuls of describeoutput. Declare difference to be a string rather than a numeric type. Read the help files for the full syntax but the basic idea is that destring pulls a set of characters from your string, and destring will convert a string variable to an integer or other format. It is important to realise that the variables have the same values, just different display formats. If you have a string variable and want to convert it to a numeric variable, you can use the encode command. 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. Stata for econ capstone stata research guides at bates.
We are here to help, but wont do your homework or help you pirate software. And, you can choose a perpetual licence, with nothing more to buy ever. It is easy to use the numeric variable, but we may also want to keep the information given from the string variable. The format tells sas how to output or store the data. String processing is fairly easy in stata because of the many builtin string functions.
A few sessions with stata will show users at least one way of approaching this problem. Stata is a complete, integrated software package that provides all your data science needsdata manipulation, visualization, statistics, and reproducible reporting. Date prev date next thread prev thread next date index thread index. How can i turn a string variable containing dates into a. In other words, i want to count the number of nonmissing observations by sedol, isin, and wsid.
Here is a rewriting of my first paragraph too late to edit the original. In stata, how do i display numeric values with commas inserted. Apparently we want to create a format for variable a so that 1 female. How can i count the number of observations by id type. Moreover, the format can influence the output of statistical procedures. You can use any word processor and save the file in ascii format, or you can use stata s dofile editor with the. How can i convert string variables to numeric variables in stata. In our dataset, there are 2 variables which are inc and ue.
This creates a variable called statadate that stores the dates in terms of days elapsed since january 1, 1960. Copying data from the internet, csv files, or other sources into stata will record the date as a string variable, shown with red color. How to prepare panel data in stata and make panel data regression in stata. Datetime data analysis with stata library guides at. On april 23, 2014, statalist moved from an email list to a forum, based at. The easiest way to convert string variables to numeric form is to use the encode command. After that, we have to specify the names of the variables which are in the wide format. Sometimes for whatever reason, string variables need to be categorical and categorical variables need to be strings. It is usually possible to adjust the numeric date or datetime values to the sentinel date and units that stata uses. This video demonstrates how to create a date variable from a date stored as a string.
Even though stata can handly string variables, it is clear in many respects that numeric variables are much preferred. How a variable appears when you look at the data with browse or edit is defined by the variables format. Quick table for converting different dates to stata format. In the i option, you list all identifying variables. To insert commas into the numeric value, use this command. How to convert numeric date to stata date stataprofessor. Similar to changing the number format, the command to change the string format is format % string lengths variable name with the optional before the number to align the display to the left. For example, suppose a numeric variable gnp has a value of 12345678. How to use local variable inside a string in stata stack. In stata this is often true because stata treats string encoded variables as missing and will not use them in analyses. Lets type confirm variable again to see what happens if the variable iprovincestate is not in our dataset.
Stata is agile, easy to use, and fast, with the ability to load and process up to 120,000 variables and over 20 billion observations. This blog post discusses the conversion of text into stata date. To concatenate is to join the characters of 2 or more variables from end to end. The string option at the end allows it to be a string rather than a numeric value. How can i quickly convert many string variables to numeric variables. Stata offers possibilities to define string variables variables containing characters or datetime variables. Stata module to leftalign or right align variables. Dec 01, 2016 this video demonstrates how to convert categorical string variables to labeled numeric variables. The format family is indicated by one or more letters. You do the same thing to leftalign a numeric variable as you do a string variable. Apr 14, 2020 this creates a variable called statadate that stores the dates in terms of days elapsed since january 1, 1960.
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. How can i convert string variables to numeric variables in. Im guessing you have declared it currently as a currency type. When stata does this, the number will look right when you browse, but attempts to run commands will turn up zero observations. Even so, because the variable is defined as str2, stata cannot perform any kind of numerical analysis of the variable science. The first case most often occurs when importing data from another source. 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. Changing string variables to numbers in stata youtube. This is a case where we want to create value labels for the numeric variable based on the string variable. There are two steps involved to convert the numeric variable to stata format. Stata s data management features give you complete control. Most the letters speak to themselves, excluding the first two variables. Editing string variables statalist the stata forum. In this case, you want to convert the actual variable, not the format type see here.
The list command confirms that the data was read correctly. Harrison 2006 acknowledges this issue and suggests an algorithm that relies on the listing of the string characteristics of variables. Many stata users also wish to convert numeric data to strings and keep the leading zeros, which is good for u. On the main stata window, click on variable manager to manage variables. Sometimes, for whatever reason, stata incorrectly calls a categorical variable a string variable. With free format data, such as method 1 above, you would type. Stata is a complete, integrated software package that provides all your data science needsdata manipulation, visualization, statistics, and automated reporting. If you have a string variable that has only numbers in it, then you can alternatively use the real function.
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