[R] quesion about lm function

[meng]

Hi all:
My data is in the attachment.
I want to analysis the mean difference of y between 2 sex.
 
My code:
result_lm<-lm(y~factor(sex) + x1 + x2)
summary(result_lm)

The result of "factor(sex)m" 136.83, is the mean difference of y between 2 sex,and the corresponding p value is 0.07618.
 
My question is: how to get the mean y of sex(m) and sex(f) respectively via lm function?
 
Many thanks for your help.
My best.

 
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