Hi. I'm beginer with STATA. I'm having a problem with categorizing variable.
I wanted to categorize income variable, so I put the code as follows,

1)
gen inc_cate=.
replace inc_cate=0 if income==.
replace inc_cate=1 if income<100
replace inc_cate=2 if income>=100 & income<300
replace inc_cate=3 if income>=300 & income<500
replace inc_cate=4 if income>=500

However, when I tabulate the inc_cate value, I couldn't find inc_cate=0,
Instead, missing values were combined with inc_cate=4.

I use the other code, using "inrange"

2)
gen inc_cate=.
replace inc_cate=0 if income==.
replace inc_cate=1 if inrange(income,0,100) ....and so on

Then, value 0 appeard when I tabulate the variable

I don't understand why this happend.

1. How can I change the first code?(not using "inrange", and change missing values into "0")
2. Are there any better code when categorizing variable(what's the code to make "
income>=100 & income<300", when using "inrange")

Thank you in advance for your valuable advices.