Print in one line dynamically

Question

I would like to make several statements that give standard output without seeing newlines in between statements   Specifically  suppose I have   for item in range 1 100       print item   The result is   1 2 3 4         How get this to instead look like   1 2 3 4 5       Even better  is it possible to print the single number over the last number  so only one number is on the screen at a time

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Like the other examples  I use a similar approach but instead of spending time calculating out the last output length  etc     I simply use ANSI code escapes to move back to the beginning of the line and then clear that entire line before printing my current status output   import sys  class Printer           Print things to stdout on one line dynamically        def   init   self data           sys stdout write   r x1b K  data   str              sys stdout flush     To use in your iteration loop you would just call something like   x   1 for f in fileList      ProcessFile f      output    File number  d completed     x     Printer output      x    1      See more here

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Change print item to    print item  in Python 2 7 print item  end      in Python 3   If you want to print the data dynamically use following syntax    print item  sep      end     flush True  in Python 3

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If you just want to print the numbers  you can avoid the loop     python 3 import time  startnumber   1 endnumber   100    solution A without a for loop start time   time clock   m   map str  range startnumber  endnumber   1   print     join m   end time   time clock   timetaken    end time - start time    1000 print  took  0 ms n  format timetaken      solution B  with a for loop start time   time clock   for i in range startnumber  endnumber   1       print i  end      end time   time clock   timetaken    end time - start time    1000 print   ntook  0 ms n  format timetaken     1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 took 21 1986929975ms  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100  took 491 466823551ms

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By the way       How to refresh it every time so it print mi in one place just change the number    It s really tricky topic  What zack suggested   outputting console control codes   is one way to achieve that   You can use  n curses  but that works mainly on  nixes   On Windows  and here goes interesting part  which is rarely mentioned  I can t understand why  you can use Python bindings to WinAPI  http   sourceforge net projects pywin32  also with ActivePython by default  - it s not that hard and works well  Here s a small example   import win32console  time  output handle   win32console GetStdHandle   win32console STD OUTPUT HANDLE   info   output handle GetConsoleScreenBufferInfo   pos   info  CursorPosition    for i in      -    -       output handle WriteConsoleOutputCharacter  i  pos       time sleep  1     Or  if you want to use print  statement or function  no difference    import win32console  time  output handle   win32console GetStdHandle   win32console STD OUTPUT HANDLE   info   output handle GetConsoleScreenBufferInfo   pos   info  CursorPosition    for i in      -    -       print i     output handle SetConsoleCursorPosition  pos       time sleep  1     win32console module enables you to do many more interesting things with windows console    I m not a big fan of WinAPI  but recently I realized that at least half of my antipathy towards it was caused by writing WinAPI code in C - pythonic bindings are much easier to use   All other answers are great and pythonic  of course  but    What if I wanted to print on previous line  Or write multiline text  than clear it and write the same lines again  My solution makes that possible

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In  9   print  Type            builtin function or method Base Class       lt type  builtin function or method  gt  String Form      lt built-in function print gt  Namespace       Python builtin Docstring      print value       sep      end   n   file sys stdout   Prints the values to a stream  or to sys stdout by default  Optional keyword arguments  file  a file-like object  stream   defaults to the current sys stdout  sep   string inserted between values  default a space  end   string appended after the last value  default a newline

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I think a simple join should work   nl      for x in range 1 10  nl append str x   print     join nl

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In Python 3 you can do it this way   for item in range 1 10       print item  end         Outputs   1 2 3 4 5 6 7 8 9    Tuple  You can do the same thing with a tuple   tup    1 2 3 4 5   for n in tup      print n  end     -      Outputs    1 - 2 - 3 - 4 - 5 -    Another example   list of tuples     1 2    A   B     3 4     Cat    Dog    for item in list of tuples      print item    Outputs    1  2    A    B    3  4    Cat    Dog     You can even unpack your tuple like this   list of tuples     1 2    A   B     3 4     Cat    Dog       Tuple unpacking so that you can deal with elements inside of the tuple individually for  item1  item2  in list of tuples      print item1  item2       Outputs   1 2 A B 3 4 Cat Dog   another variation   list of tuples     1 2    A   B     3 4     Cat    Dog    for  item1  item2  in list of tuples      print item1      print item2      print   n     Outputs   1 2   A B   3 4   Cat Dog

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for item in range 1 100       if item  99          print item end         else          print  item end        Output  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99

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A comma at the end of the print statement omits the new line    for i in xrange 1 100     print i    but this does not overwrite

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You can add a trailing comma to your print statement to print a space instead of a newline in each iteration   print item    Alternatively  if you re using Python 2 6 or later  you can use the new print function  which would allow you to specify that not even a space should come at the end of each item being printed  or allow you to specify whatever end you want    from   future   import print function     print item  end       Finally  you can write directly to standard output by importing it from the sys module  which returns a file-like object   from sys import stdout     stdout write  str item

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By the way       How to refresh it every time so it print mi in one place just change the number    In general  the way to do that is with terminal control codes   This is a particularly simple case  for which you only need one special character  U 000D CARRIAGE RETURN  which is written   r  in Python  and many other languages    Here s a complete example based on your code   from sys import stdout from time import sleep for i in range 1 20       stdout write   r d    i      stdout flush       sleep 1  stdout write   n     move the cursor to the next line   Some things about this that may be surprising    The  r goes at the beginning of the string so that  while the program is running  the cursor will always be after the number   This isn t just cosmetic  some terminal emulators get very confused if you do it the other way around  If you don t include the last line  then after the program terminates  your shell will print its prompt on top of the number  The stdout flush is necessary on some systems  or you won t get any output   Other systems may not require it  but it doesn t do any harm    If you find that this doesn t work  the first thing you should suspect is that your terminal emulator is buggy   The vttest program can help you test it   You could replace the stdout write with a print statement but I prefer not to mix print with direct use of file objects

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For those struggling as I did  I came up with the following that appears to work in both python 3 7 4 and 3 5 2   I expanded the range from 100 to 1 000 000 because it runs very fast and you may not see the output  This is because one side effect of setting end   r  is that the final loop iteration clears all of the output  A longer number was needed to demonstrate that it works  This result may not be desirable in all cases  but was fine in mine  and OP didn t specify one way or another  You could potentially circumvent this with an if statement that evaluates the length of the array being iterated over  etc  The key to get it working in my case was to couple the brackets      with  format    Otherwise  it didn t work   Below should work as-is      usr bin env python3  for item in range 1 1000000       print      format item   end   r   flush True

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Or even simpler   import time a   0 while True      print  a  end   r       a    1     time sleep 0 1    end   r  will overwrite from the beginning  0   of the first print

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To make the numbers overwrite each other  you can do something like this   for i in range 1 100       print   r  i    That should work as long as the number is printed in the first column   EDIT  Here s a version that will work even if it isn t printed in the first column   prev digits   -1 for i in range 0 1000       print   s d       b   prev digits   1   i        prev digits   len str i     I should note that this code was tested and works just fine in Python 2 5 on Windows  in the WIndows console  According to some others  flushing of stdout may be required to see the results  YMMV

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Another answer that I m using on 2 7 where I m just printing out a     every time a loop runs  to indicate to the user that things are still running  is this   print   b      It prints the     characters without spaces between each  It looks a little better and works pretty well  The  b is a backspace character for those wondering

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Use print item  to make the print statement omit the newline   In Python 3  it s print item  end        If you want every number to display in the same place  use for example  Python 2 7    to   20 digits   len str to - 1   delete     b     digits   1  for i in range to       print   0  1  2    format delete  i  digits     In Python 3  it s a bit more complicated  here you need to flush sys stdout or it won t print anything until after the loop has finished   import sys to   20 digits   len str to - 1   delete     b     digits  for i in range to      print   0  1  2    format delete  i  digits   end        sys stdout flush

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for Python 2 7  for x in range 0  3       print x    for Python 3  for x in range 0  3       print x  end

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The best way to accomplish this is to use the  r character  Just try the below code   import time for n in range 500     print n  end   r     time sleep 0 01  print      start new line so most recently printed number stays

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change  print item   to  print   033 K   item    r   sys stdout flush        033 K  clears to the end of the line  the  r  returns to the beginning of the line  the flush statement makes sure it shows up immediately so you get real-time output

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So many complicated answers  If you have python 3  simply put  r at the start of the print  and add end     flush True to it   import time  for i in range 10       print f  r i  foo bar   end     flush True      time sleep 0 5    This will write 0 foo bar  then 1 foo bar etc  in-place

[python] Print in one line dynamically

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