Move an item inside a list

Question

In Python  how do I move an item to a definite index in a list

User · Answer

I profiled a few methods to move an item within the same list with timeit. Here are the ones to use if j>i:

+---------------------------------+
¦ 14.4usec ¦ x[i:i]=x.pop(j),     ¦
¦ 14.5usec ¦ x[i:i]=[x.pop(j)]    ¦
¦ 15.2usec ¦ x.insert(i,x.pop(j)) ¦
+---------------------------------+

and here the ones to use if j<=i:

+--------------------------------------+
¦ 14.4usec ¦ x[i:i]=x[j],;del x[j]     ¦
¦ 14.4usec ¦ x[i:i]=[x[j]];del x[j]    ¦
¦ 15.4usec ¦ x.insert(i,x[j]);del x[j] ¦
+--------------------------------------+

Not a huge difference if you only use it a few times, but if you do heavy stuff like manual sorting, it's important to take the fastest one. Otherwise, I'd recommend just taking the one that you think is most readable.

User · Answer

Use the insert method of a list   l   list      l insert index  item    Alternatively  you can use a slice notation   l index index     item    If you want to move an item that s already in the list to the specified position  you would have to delete it and insert it at the new position   l insert newindex  l pop oldindex

User · Answer

If you don t know the position of the item  you may need to find the index first   old index   list1 index item    then move it   list1 insert new index  list1 pop old index     or IMHO a cleaner way   try    list1 remove item    list1 insert new index  item  except ValueError    pass

User · Answer

A slightly shorter solution  that only moves the item to the end  not anywhere is this   l     l pop 0     For example    gt  gt  gt  l    1 2 3 4 5   gt  gt  gt  l     l pop 0    gt  gt  gt  l  2  3  4  5  1

User · Answer

A solution very simple  but you have to know the index of the original position and the index of the new position   list1 index1  list1 index2  list1 index2  list1 index1

User · Answer

l   list      if item in l      l remove item     checks if the item to be moved is present in the list  l insert new index item

[python] Move an item inside a list?

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