iken0 https://blog.hatena.ne.jp/iken0/ ロバの耳 https://iken0.hatenadiary.org/ ruby number p "ff".hex #=> 255 p sprintf("0x%04x", "a5".hex) # 16進数にする #=> "0x00a5" p [0,16,32,128,255].pack('c*').unpack('H*') #=> ["00102080ff"] p ["ff20"].pack('H*').unpack('C*') # 符号無し #=> [255, 32] p ["ff20"].pack('H*').unpack('c*') # 符号あり #=> [-1, 32] p 0xffff.to_s(10) #=> "65535" p 31.to_s(16) #=> "1f" 190 <iframe src="https://hatenablog-parts.com/embed?url=https%3A%2F%2Fiken0.hatenadiary.org%2Fentry%2F20070518%2Fp4" title="16進数を10進数にする - ロバの耳" class="embed-card embed-blogcard" scrolling="no" frameborder="0" style="display: block; width: 100%; height: 190px; max-width: 500px; margin: 10px 0px;"></iframe> Hatena Blog https://hatena.blog 2007-05-18 00:00:04 rich https://iken0.hatenadiary.org/entry/20070518/p4 1.0 100%