for loop skipping 1st and 2nd element

Question

Since Wednesday, for loop is not working correctly in Python(2.7) in (with windows 10). See screen shot. Its skipping the 1st and somestimes the 2nd element (index 0 and 1). A similar while loop works fine.

Screen shot of simple example. For loop skips index 0 and 1. While loop wrks fine

`i` is the element not the index... and post code & errors as text, not images. — Jean-François Fabre, May 05 '17 at 09:32
Possible duplicate of [Looping Through List Returns Negative Index](http://stackoverflow.com/questions/43525168/looping-through-list-returns-negative-index) — Jean-François Fabre, May 05 '17 at 09:37
When you do `for i in list` then i becomes an element of the list not an index, so you cannot do `list[i]` — , May 05 '17 at 09:38

score 1 · Answer 1 · answered May 05 '17 at 09:37

1

Okay, so if you are using for loop you should either go:

for i in my_list:
    print i

Or:

for i, element in enumerate(my_list):
    print my_list[i]

In both cases don't call your variable list as it is a reserved keyword for actual list.

answered May 05 '17 at 09:37

zipa

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score 0 · Answer 2 · answered May 05 '17 at 11:38

You already have an answer but hopefully this might explain what is going on

>>> l =[1,2,3,4]
>>> l
[1, 2, 3, 4]
>>> for i in l:
...  print "value of i=",str(i), "value of l at index[i]", str(l[i])
... 
value of i= 1 value of l at index[i] 2
value of i= 2 value of l at index[i] 3
value of i= 3 value of l at index[i] 4
value of i= 4 value of l at index[i]
Traceback (most recent call last):
  File "<stdin>", line 2, in <module>
IndexError: list index out of range

There is no value available at l[4] as the starting position is l[0] through to l[3]

for loop skipping 1st and 2nd element

2 Answers2