ValueError could not convert string to float id

Question

I m running the following python script      usr bin python  import os sys from scipy import stats import numpy as np  f open  data2 txt    r   readlines   N len f -1 for i in range 0 N       w f i  split       l1 w 1 8      l2 w 8 15      list1  float x  for x in l1      list2  float x  for x in l2      result stats ttest ind list1 list2      print result 1    However I got the errors like   ValueError  could not convert string to float  id   I m confused by this  When I try this for only one line in interactive section  instead of for loop using script    gt  gt  gt  from scipy import stats  gt  gt  gt  import numpy as np  gt  gt  gt  f open  data2 txt   r   readlines    gt  gt  gt  w f 1  split    gt  gt  gt  l1 w 1 8   gt  gt  gt  l2 w 8 15   gt  gt  gt  list1  float x  for x in l1   gt  gt  gt  list1  5 3209183842  4 6422726719  4 3788135547  5 9299061614  5 9331108706  5 0287087832  4 57       It works well   Can anyone explain a little bit about this  Thank you

User · Answer

I solved the similar situation with basic technique using pandas. First load the csv or text file using pandas.It's pretty simple

data=pd.read_excel('link to the file')

Then set the index of data to the respected column that needs to be changed. For example, if your data has ID as one attribute or column, then set index to ID.

 data = data.set_index("ID")

Then delete all the rows with "id" as the value instead of number using following command.

  data = data.drop("id", axis=0).

Hope, this will help you.

User · Answer

Your data may not be what you expect -- it seems you re expecting  but not getting  floats   A simple solution to figuring out where this occurs would be to add a try except to the for-loop     for i in range 0 N       w f i  split       l1 w 1 8      l2 w 8 15      try        list1  float x  for x in l1        list2  float x  for x in l2      except ValueError  e          report the error in some way that is helpful -- maybe print out i     result stats ttest ind list1 list2      print result 1

User · Answer

This error is pretty verbose   ValueError  could not convert string to float  id   Somewhere in your text file  a line has the word id in it  which can t really be converted to a number   Your test code works because the word id isn t present in line 2     If you want to catch that line  try this code  I cleaned your code up a tad      usr bin python  import os  sys from scipy import stats import numpy as np  for index  line in enumerate open  data2 txt    r   readlines         w   line split          l1   w 1 8      l2   w 8 15       try          list1   map float  l1          list2   map float  l2      except ValueError          print  Line  i  is corrupt   format i   index           break      result   stats ttest ind list1  list2      print result 1

User · Answer

Obviously some of your lines don t have valid float data  specifically some line have text id which can t be converted to float    When you try it in interactive prompt you are trying only first line  so best way is to print the line where you are getting this error and you will know the wrong line e g      usr bin python  import os sys from scipy import stats import numpy as np  f open  data2 txt    r   readlines   N len f -1 for i in range 0 N       w f i  split       l1 w 1 8      l2 w 8 15      try          list1  float x  for x in l1          list2  float x  for x in l2      except ValueError e          print  error  e  on line  i     result stats ttest ind list1 list2      print result 1

User · Answer

Perhaps your numbers aren t actually numbers  but letters masquerading as numbers   In my case  the font I was using meant that  l  and  1  looked very similar  I had a string like  l1919  which I thought was  11919  and that messed things up

User · Answer

My error was very simple  the text file containing the data had some space  so not visible  character on the last line     As an output of grep  I had 45   instead of just 45

[python] ValueError: could not convert string to float: id

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