Stata Question- Is the code "gen var1=var2 if conditions" possible ?

[Salma Stati]

Hello,
I am new to Stata and I would like to write a code.
I want to determine the number of children in the women's current union (variable childincurunion).
I have data on : the birth year of the children (variable yearbirthchild) the year of first marriage/cohabitation (yearofmarriage) and data on the total number of alive children that the woman had regarding the number of union that she may had (variable chebalive) .
I am restricting my sample to the number of women who are currently married or living with a man and had only one union.
gen childIncurrunion=0
replace childincurrunion=1 if yearbirthchild>=yearofmarriage (if we believe that the couple has children when they are married and not)
Then, (for this line stata says invalid syntax).
gen numberchildincurrunion=0
if childincurrunion=0
replace numberchildincurrunion=totalnumberofchildren
What's the problem with this syntax ? Is there a correct way to write this ?
Thank you for your help.
I really appreciate it

[Carlo Lazzaro]

Salma:
welcome to this forum.
As per FAQ, please use CODE delimiters to share what you typed and what Stata gave you back. In addition, you can post an example/excerpt of your data via -dataex-. Thanks.
As far as your question is concerned, please note that the -uf- clause needs a double == to work, as in the following toy-example (-regress- outcome table was omitted):

sysuse auto.dta
regress price mpg if rep78==5

[Leonardo Guizzetti]

Welcome Salma. As you are new to Stata, it would be a very good investment of time to read the Getting Started guide which is included as part of the PDF documentation with your Stata installation. Type -help getting started- to get started.

[Salma Stati]

Thank you both for your answers )
Carlo - What you suggested worked !

Salma
(Stata 15.1 IC)