UnboundLocalError local variable referenced before assignment after an if statement

Question

I have also tried searching for the answer but I don t understand the answers to other people s similar problems     tfile  open   home path to file   r     def temp sky lreq  breq       for line in tfile          data   line split           if      abs float data 0   - lreq   lt   0 1              and abs float data 1   - breq   lt   0 1                           T  data 2      return T print temp sky 60  60  print temp sky 10  -10    I get the following error   7 37052488 Traceback  most recent call last   File  tsky py   line 25  in  lt module gt    print temp sky 10  -10  File  tsky py   line 22  in temp sky   return T UnboundLocalError  local variable  T  referenced before assignment   The first print statement works correctly but it won t work for the second  I have tried making T a global variable but this makes both answers the same  Please help

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To Solve this Error just initialize that variable above that loop or statement  For Example var a

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FWIW  I got the same error for a different reason   I post the answer here not for the benefit of the OP  but for the benefit of those who may end up on this page due to its title    who might have made the same mistake I did   I was confused why I was getting  local variable referenced before assignment  because I was calling a FUNCTION that I knew was already defined   def job fn job     return job     job   def do something      a   1   b   2   job fn   job fn  foo    do something     This was giving   UnboundLocalError  local variable  job fn  referenced before assignment   Took me a while to see my obvious problem  I used a local variable named job fn which masked the ability to see the prior function definition for job fn

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Before I start  I d like to note that I can t actually test this since your script reads data from a file that I don t have    T  is defined in a local scope for the declared function  In the first instance  T  is assigned the value of  data 2   because the conditional statement above apparently evaluates to True  Since the second call to the function causes the  UnboundLocalError  exception to occur  the local variable  T  is getting set and the conditional assignment is never getting triggered   Since you appear to want to return the first bit of data in the file that matches your conditonal statement  you might want to modify you function to look like this   def temp sky lreq  breq       for line in tfile          data   line split           if   abs float data 0   - lreq   lt   0 1 and abs float data 1   - breq   lt   0 1                           return data 2      return None   That way the desired value gets returned when it is found  and  None  is returned when no matching data is found

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I was facing same issue in my exercise  Although not related  yet might give some reference  I didn t get any error once I placed addition result   0 inside function  Hope it helps  Apologize if this answer is not in context   user input   input  Enter multiple values separated by comma  gt      def add numbers num list       addition result   0     for i in num list          addition result   addition result   i     print addition result   add numbers user input

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Contributing to ferrix example    class Battery         def   init   self  battery size   60           self battery size   battery size     def get range self           if self battery size    70              range   240         elif self battery size    85          range   270          message    This car can go approx     str range          message     Fully charge          print message    My message will not execute  because none of my conditions  are fulfill therefore receiving   UnboundLocalError  local variable  range  referenced before assignment    def get range self       if self battery size  lt   70          range   240     elif self battery size  gt   85          range   270

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The other answers are correct  You don t have a default value  However  you have another problem in your logic   You read the same file twice  After reading it once  the cursor is at the end of the file  To solve this  you can do two things  Either open close the file upon each function call   def temp sky lreq  breq       with open   home path to file   r   as tfile            do your stuff   This hase the disadvantage of having to open the file each time  The better way would be   tfile seek 0    You do this after your for line in tfile  loop  It resets the cursor to the beginning to the next call will start from there again

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Your if statement is always false and T gets initialized only if a condition is met  so the code doesn t reach the point where T gets a value  and by that  gets defined bound   You should introduce the variable in a place that always gets executed   Try   def temp sky lreq  breq       T    lt some default value gt    None is often a good pick     for line in tfile          data   line split           if abs float data 0  -lreq   lt   0 1 and abs float data 1  -breq   lt   0 1                          T   data 2      return T

[python] "UnboundLocalError: local variable referenced before assignment" after an if statement

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