How Many Characters Are There Where The Radical Is The Same As The Main Component? How Many Characters Are There Where The Radical Is The Same As The Main Component?


Example:

字海网: 


  


字海网: 


  


This question is definitely answerable as there are only a certain amount of radicals.
A quick perusal of my database gives me

u-cjk/6299      抙  ⿰扌手
u-cjk/726a      牪  ⿰牜牛
u-cjk/72be      犾  ⿰犭犬
u-cjk/73cf      珏  ⿰王玉
u-cjk/8aa9      誩  ⿰言言
u-cjk/8e00      踀  ⿰足
u-cjk-xa/3908   㤈  ⿰忄心
u-cjk-xb/201a7    ⿰亻人
u-cjk-xb/23c99    ⿰氵水
u-cjk/9342      鍂  ⿰金金


(considering only Unicode code points). I tested against the RegEx 氵水|礻示|⺬示|釒金|钅金|王玉|忄心|竹|讠言|言言|冫氷|扌手|足|⻗雨|爫爪|亻人|火灬|犭犬|牜牛|飠食|食|饣食, which may be incomplete. 

In related news, a search for 水水|示示|金金|王王|玉玉|心心|竹竹|手手|足足|雨雨|爪爪|人人|火火|犬犬|牛牛|食食 brings up, amongst others, these:

u-cjk/4ece      从  ⿰人人
u-cjk/6c9d      沝  ⿰水水
u-cjk/708f      炏  ⿰火火
u-cjk/73a8      玨  ⿰王王
u-cjk/7958      祘  ⿰示示
u-cjk-xa/3e5c   㹜  ⿰犬犬
u-cjk-xb/225f0    ⿰心心
u-cjk-xb/22a92    ⿰手手
u-cjk-xb/24519    ⿱爪⿰爪爪
u-cjk-xb/24934    ⿰玉玉
u-cjk-xb/25d12    ⿱竹⿰竹竹


some of which may violate your expectations about how to correctly write characters, as the usual positional variants are not used in these forms.