String compare in Perl with eq vs

Question

I am  a complete Perl newbie  doing string compare in an if statement   If I do following   if   str1     taste   amp  amp   str2     waste         I see the correct result  i e  if the condition matches  it evaluates the  then  block   But I see these warnings      Argument  taste  isn t numeric in numeric eq      at line number x     Argument  waste  isn t numeric in numeric eq      at line number x    But if I do   if   str1 eq  taste   amp  amp   str2 eq  waste         Even if the if condition is satisfied  it doesn t evaluate the  then  block   Here   str1 is taste and  str2 is waste   How should I fix this

User · Answer

does a numeric comparison  it converts both arguments to a number and then compares them   As long as  str1 and  str2 both evaluate to 0 as numbers  the condition will be satisfied   eq does a string comparison  the two arguments must match lexically  case-sensitive  for the condition to be satisfied    foo      bar       True  both strings evaluate to 0   foo  eq  bar       False  the strings are not equivalent   Foo  eq  foo       False  the F characters are different cases   foo  eq  foo       True  both strings match exactly

User · Answer

First  eq is for comparing strings     is for comparing numbers      Even if the  if  condition is satisfied  it doesn t evaluate the  then  block    I think your problem is that your variables don t contain what you think they do  I think your  str1 or  str2 contains something like  taste n  or so  Check them by printing before your if  print  str1   str1  n     The trailing newline can be removed with the chomp  str1   function

User · Answer

Did you try to chomp the  str1 and  str2   I found a similar issue with using  another   str1 eq  Y  and it only went away when I first did   chomp  str1   if   str1 eq  Y              works after that    Hope that helps

User · Answer

Maybe the condition you are using is incorrect    str1     taste   amp  amp   str2     waste    The program will enter into THEN part only when both of the stated conditions are true   You can try with  str1     taste      str2     waste   This will execute the THEN part if anyone of the above conditions are true

[string] String compare in Perl with "eq" vs "=="

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