binary search string help

[kietrichards]

Hi! I'm trying to look for a word in my list by way of binary search. But sth doesn;t work. Can sb have a look at it? ;) Thanks!

infile = open("clean.acc", "r") firstlist = [] for line in infile: firstlist.append(line) first = 0 last = len(firstlist)-1 done = False acc = input("Enter your acc nr") while first<=last and not done: mid = (first+last)//2 if firstlist[mid] == acc: done = True print(done) else: if firstlist[mid] > acc: last = mid-1 else: first = mid+1 infile.close()

[stullis]

Just a little refactoring and it works. I restructured the if statements into a single if...elif...else. The main problem was the mid assignment. Dividing by 2 generates a float and floats cannot be used in indexing; the interpreter would raise an error when trying firstlist[mid] because it's firstlist[4.5] (supposing a nine item list).

infile = open("clean.acc", "r") firstlist = [] for line in infile: firstlist.append(line) first = 0 last = len(firstlist)-1 done = False acc = input("Enter your acc nr") while first<=last and not done: mid = int((first+last)//2) if acc < firstlist[mid]: first = mid elif acc == firstlist[mid]: done = True print(done) else: last = mid infile.close()