Decimal Digit Truncating
Python 2, 103 101 98 94 93 87 bytes



a,b=input().split('.');i,w=0,len(b)
while w&gt;i:w=min(int(b[i]),w);i+=1
print a+'.'+b[:w]


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Saved:


-2 bytes, thanks to Kevin Cruijssen
-3 bytes, thanks to Vedant Kandoi
-4 bytes, thanks to Lynn