How to prevent reading next line when next() is used in an if statement

Question

I have the lines:

for line in f:
    if 'ipsum' in next(f):    #just want to check
        print("Hello")

What I want is to only check what is there on the next line, not overall jump to the next line. What I want is something like:

for line in f:
    if 'ipsum' in next(f):    #just checking
        print("Hello")
        next(f) #then actually jump to the next line

Is there any other way to do this?

''' junk.txt is: one two three ... ten ''' import sys filehandle = open("junk.txt", "r") lines = filehandle.readlines() currentline = 0 for line in lines: if currentline == len(lines) - 1: continue nextline = currentline + 1 if "three" in lines[nextline]: print (line) currentline += 1 #tried to answer this, wrote it up and now can't submit an answer :( This works. — sniperd, Nov 09 '17 at 19:02

score 0 · Answer 1 · answered Nov 09 '17 at 18:50

0

I am afraid you can not do that this way. I think you will have to use a list to store the lines of your file. You are using an iterator and you can not see what is next without actually calling next()

answered Nov 09 '17 at 18:50

lpozo

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How to prevent reading next line when next() is used in an if statement

1 Answers1