Question

hi I m wrtng a very simple Python Program to implement Binary Search.

tup=input("enter tup:")
start=0
length=len[tup]
end=tup[length-1]
mid=(int(start)+int(end))/2
key=input("enter value to search")
def search(start,end,key):
  if key==tup[mid]
    print mid
  else if key<tup[mid]
    search(start,mid,key)
  else if key>tup[mid]
    search(mid,end,key)
  else
    return(-1) 

I get an error as

File "binsearch.py", line 8
if key==tup[mid]
               ^

SyntaxError: invalid syntax

I believe I m missing something trivial but unable to figure out.! Let me know if u feel there are any other errors. thanks 🙂

Answer 1

• You need to end all statements that begin a new block with : (i.e. the statements where you increase the indentation level in the next line)
• You need to replace else if X with elif X:
• You should use raw_input instead of input as the latter evals whatever the user entered.
• return is a statement, not a function, so you do not need () around the return value.