How can I convert a string to a number in Perl

Question

I have a string which holds a decimal value in it and I need to convert that string into a floating point variable  So an example of the string I have is  5 45  and I want a floating point equivalent so I can add  1 to it  I have searched around the internet  but I only see how to convert a string to an integer

User · Answer

This is a simple solution   Example 1  my  var1    123abc   print  var1   0    Result  123   Example 2  my  var2    abc123   print  var2   0    Result  0

User · Answer

Perl really only has three types  scalars  arrays  and hashes   And even that distinction is arguable       The way each variable is treated depends on what you do with it     perl -e  print 5 4   3 4   5 43 4     perl -e  print  5 4     3 4    8 8

User · Answer

You don t need to convert it at all     perl -e  print  5 45    0 1   5 55

User · Answer

Perl is weakly typed and context based  Many scalars can be treated both as strings and numbers  depending on the operators you use   a   7 6   b   7x6  print   a  b n   You get 42 777777   There is a subtle difference  however  When you read numeric data from a text file into a data structure  and then view it with Data  Dumper  you ll notice that your numbers are quoted  Perl treats them internally as strings  Read  my hash  1     2 if            n    Dump  foo      42   If you want unquoted numbers in the dump  Read  my hash  1     2 0 if            n    Dump  foo     42  After  2 0 Perl notices that you ve treated  2 as a number  because you used a numeric operator    I noticed this whilst trying to compare two hashes with Data  Dumper

User · Answer

Perl is a context-based language  It doesn t do its work according to the data you give it  Instead  it figures out how to treat the data based on the operators you use and the context in which you use them  If you do numbers sorts of things  you get numbers     numeric addition with strings  my  sum    5 45     0 01     5 46   If you do strings sorts of things  you get strings     string replication with numbers  my  string     45 2   x 4     22 522 522 522 5    Perl mostly figures out what to do and it s mostly right  Another way of saying the same thing is that Perl cares more about the verbs than it does the nouns   Are you trying to do something and it isn t working

User · Answer

In comparisons it makes a difference if a scalar is a number of a string  And it is not always decidable  I can report a case where perl retrieved a float in  scientific  notation and used that same a few lines below in a comparison   use strict       next unless  line     and your result is  s        my  val    1  if   val  lt  0 001       print  this is small n       And here  val was not interpreted as numeric for e g   2e-77  retrieved from  line  Adding 0  or 0 0 for good ole C programmers  helped

User · Answer

Google lead me here while searching on the same question phill asked  sorting floats  so I figured it would be worth posting the answer despite the thread being kind of old   I m new to perl and am still getting my head wrapped around it but brian d foy s statement  Perl cares more about the verbs than it does the nouns   above really hits the nail on the head   You don t need to convert the strings to floats before applying the sort   You need to tell the sort to sort the values as numbers and not strings  i e   my  foo     1 2    3 4    2 1    4 6    my  foo sort   sort   a  lt   gt   b   foo    See http   perldoc perl org functions sort html for more details on sort

User · Answer

As I understand it int   is not intended as a  cast  function for designating data type it s simply being  ab used here to define the context as an arithmetic one   I ve  ab used  0  val  in the past to ensure that  val is treated as a number

User · Answer

Perl really only has three types  scalars  arrays  and hashes   And even that distinction is arguable       The way each variable is treated depends on what you do with it     perl -e  print 5 4   3 4   5 43 4     perl -e  print  5 4     3 4    8 8

User · Answer

var    0   probably what you want  Be warned however  if  var is string could not be converted to numeric  you ll get the error  and  var will be reset to 0   my  var    abc123   print  var    var n    var    0  print  var    var n     logs  var   abc123 Argument  abc123  isn t numeric in addition     at test pl line 7  var   0

User · Answer

You don t need to convert it at all     perl -e  print  5 45    0 1   5 55

User · Answer

As I understand it int   is not intended as a  cast  function for designating data type it s simply being  ab used here to define the context as an arithmetic one   I ve  ab used  0  val  in the past to ensure that  val is treated as a number

User · Answer

You don t need to convert it at all     perl -e  print  5 45    0 1   5 55

User · Answer

Perl is weakly typed and context based  Many scalars can be treated both as strings and numbers  depending on the operators you use   a   7 6   b   7x6  print   a  b n   You get 42 777777   There is a subtle difference  however  When you read numeric data from a text file into a data structure  and then view it with Data  Dumper  you ll notice that your numbers are quoted  Perl treats them internally as strings  Read  my hash  1     2 if            n    Dump  foo      42   If you want unquoted numbers in the dump  Read  my hash  1     2 0 if            n    Dump  foo     42  After  2 0 Perl notices that you ve treated  2 as a number  because you used a numeric operator    I noticed this whilst trying to compare two hashes with Data  Dumper

User · Answer

Perl is a context-based language  It doesn t do its work according to the data you give it  Instead  it figures out how to treat the data based on the operators you use and the context in which you use them  If you do numbers sorts of things  you get numbers     numeric addition with strings  my  sum    5 45     0 01     5 46   If you do strings sorts of things  you get strings     string replication with numbers  my  string     45 2   x 4     22 522 522 522 5    Perl mostly figures out what to do and it s mostly right  Another way of saying the same thing is that Perl cares more about the verbs than it does the nouns   Are you trying to do something and it isn t working

User · Answer

Google lead me here while searching on the same question phill asked  sorting floats  so I figured it would be worth posting the answer despite the thread being kind of old   I m new to perl and am still getting my head wrapped around it but brian d foy s statement  Perl cares more about the verbs than it does the nouns   above really hits the nail on the head   You don t need to convert the strings to floats before applying the sort   You need to tell the sort to sort the values as numbers and not strings  i e   my  foo     1 2    3 4    2 1    4 6    my  foo sort   sort   a  lt   gt   b   foo    See http   perldoc perl org functions sort html for more details on sort

User · Answer

In comparisons it makes a difference if a scalar is a number of a string  And it is not always decidable  I can report a case where perl retrieved a float in  scientific  notation and used that same a few lines below in a comparison   use strict       next unless  line     and your result is  s        my  val    1  if   val  lt  0 001       print  this is small n       And here  val was not interpreted as numeric for e g   2e-77  retrieved from  line  Adding 0  or 0 0 for good ole C programmers  helped

User · Answer

Perl really only has three types  scalars  arrays  and hashes   And even that distinction is arguable       The way each variable is treated depends on what you do with it     perl -e  print 5 4   3 4   5 43 4     perl -e  print  5 4     3 4    8 8

User · Answer

Perl really only has three types  scalars  arrays  and hashes   And even that distinction is arguable       The way each variable is treated depends on what you do with it     perl -e  print 5 4   3 4   5 43 4     perl -e  print  5 4     3 4    8 8

User · Answer

Perl is a context-based language  It doesn t do its work according to the data you give it  Instead  it figures out how to treat the data based on the operators you use and the context in which you use them  If you do numbers sorts of things  you get numbers     numeric addition with strings  my  sum    5 45     0 01     5 46   If you do strings sorts of things  you get strings     string replication with numbers  my  string     45 2   x 4     22 522 522 522 5    Perl mostly figures out what to do and it s mostly right  Another way of saying the same thing is that Perl cares more about the verbs than it does the nouns   Are you trying to do something and it isn t working

User · Answer

var    0   probably what you want  Be warned however  if  var is string could not be converted to numeric  you ll get the error  and  var will be reset to 0   my  var    abc123   print  var    var n    var    0  print  var    var n     logs  var   abc123 Argument  abc123  isn t numeric in addition     at test pl line 7  var   0

User · Answer

This is a simple solution   Example 1  my  var1    123abc   print  var1   0    Result  123   Example 2  my  var2    abc123   print  var2   0    Result  0

User · Answer

Perl is a context-based language  It doesn t do its work according to the data you give it  Instead  it figures out how to treat the data based on the operators you use and the context in which you use them  If you do numbers sorts of things  you get numbers     numeric addition with strings  my  sum    5 45     0 01     5 46   If you do strings sorts of things  you get strings     string replication with numbers  my  string     45 2   x 4     22 522 522 522 5    Perl mostly figures out what to do and it s mostly right  Another way of saying the same thing is that Perl cares more about the verbs than it does the nouns   Are you trying to do something and it isn t working

User · Answer

You don t need to convert it at all     perl -e  print  5 45    0 1   5 55

[string] How can I convert a string to a number in Perl?

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