Convert array values from string to int

Question

The following code   string    quot 1 2 3 quot   ids   explode       string   var dump  ids    Returns the array  array 3       0   gt    string 1   quot 1 quot     1   gt    string 1   quot 2 quot     2   gt    string 1   quot 3 quot     I need for the values to be of type int instead of type string  Is there a better way of doing this than looping through the array with foreach and converting each string to int

User · Answer

Use this code with a closure  introduced in PHP 5 3   it s a bit faster than the accepted answer and for me  the intention to cast it to an integer  is clearer      if you have your values in the format  1 2 3 4   use this before      stringArray   explode       1 2 3 4      stringArray     1    2    3    4      intArray   array map      function  value    return  int  value          stringArray     var dump  intArray     Output will be   array 4       0   gt    int 1     1   gt    int 2     2   gt    int 3     3   gt    int 4

User · Answer

PHP 7 4 style    ids   array map fn string  x   int   gt   int   x  explode       string

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If you have array like     runners     1   2   3   4      And if you want to covert them into integers and keep within array  following should do the job    newArray   array map  create function   value    return  int  value                  runners

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Input        3   6   16   120     Type conversion I used     int  s   function Str Int Arr  data        h          arr substr  data 1 -1          exp str replace           arr        exp str replace            arr        s           m 0      foreach  str split  exp  as  k           if  0  lt    k  amp  amp   9  gt  k     k                    if  0   lt    k  amp  amp   9   gt   k                    s   k                   h  m   int  s               else                   s                      m  1                                       return  h    var dump Str Int Arr    3   6   16   120         Output   array 4       0   gt    int 3     1   gt    int 6     2   gt    int 16     3   gt    int 120      Thanks

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My solution is casting each value with the help of callback function    ids   array map  function  value    return  int  value      ids

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So I was curious about the performance of some of the methods mentioned in the answers for large number of integers   Preparation  Just creating an array of 1 million random integers between 0 and 100   Than  I imploded them to get the string      integers   array       for   i   0   i  lt  1000000   i             integers     rand 0  100           long string   implode       integers     Method 1  This is the one liner from Mark s answer     integerIDs   array map  intval   explode       long string      Method 2  This is the JSON approach      integerIDs   json decode        long string        true     Method 3  I came up with this one as modification of Mark s answer  This is still using explode   function  but instead of calling array map   I m using regular foreach loop to do the work to avoid the overhead array map   might have   I am also parsing with  int  vs intval    but I tried both  and there is not much difference in terms of performance       result array   array       strings array   explode       long string      foreach   strings array as  each number           result array      int   each number        Results    Method 1        Method 2        Method 3 0 4804770947    0 3608930111    0 3387751579 0 4748001099    0 363986969     0 3762528896 0 4625790119    0 3645150661    0 3335959911 0 5065748692    0 3570590019    0 3365750313 0 4803431034    0 4135499001    0 3330330849 0 4510772228    0 4421861172    0 341176033 0 503674984     0 3612480164    0 3561749458 0 5598649979    0 352314949     0 3766179085 0 4573421478    0 3527538776    0 3473439217  0 4863037268    0 3742785454    0 3488383293   The bottom line is the average   It looks like the first method was a little slower for 1 million integers  but I didn t notice 3x performance gain of Method 2 as stated in the answer   It turned out foreach loop was the quickest one in my case   I ve done the benchmarking with Xdebug   Edit  It s been a while since the answer was originally posted   To clarify  the benchmark was done in php 5 6

User · Answer

Another technique is to type-hint  coerce  the incoming values to int type after exploding the string  Note that these techniques will work as demonstrated in my demo link unless you have set php to use strict typing  The following techniques should not be used to sanitize non-numeric strings  it assumes that all values will be numeric  If float values are passed into these techniques  they will be truncated floored to integers  Code   Demo   string    quot 1 2 3 quot    array   explode       string   var dump  array    echo  quot  n--- n quot   array walk  array  function int  amp  int       var dump  array    echo  quot  n--- n quot   var dump      array map function int  i   return  i     explode       string       echo  quot  n--- n quot   var dump      array map fn int  i    gt   i  explode       string      PHP 7 4 arrow function syntax     Output  array 3       0   gt  string 1   quot 1 quot     1   gt  string 1   quot 2 quot     2   gt  string 1   quot 3 quot     --- array 3       0   gt  int 1     1   gt  int 2     2   gt  int 3     --- array 3       0   gt  int 1     1   gt  int 2     2   gt  int 3     --- array 3       0   gt  int 1     1   gt  int 2     2   gt  int 3

User · Answer

In Mark s solution  you will return array  0   gt  int 0  if you try to parse a string such as  test     integerIDs   array map   intval   array filter  explode       string    is numeric

User · Answer

This is almost 3 times faster than explode    array map   and intval      integerIDs   json decode        string        true

User · Answer

An alternative shorter method could be    r   explode       s   foreach   r as  amp  i   i    int   i    It has the same performance as Method 3

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lt  php       string    quot 1 2 3 quot    ids   explode       string     array walk   ids  function    amp  id          id    int   id      var dump   ids

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Not sure if this is faster but flipping an array twice will cast numeric strings to integers   string    quot 1 2 3 bla quot    ids   array flip array flip explode       string     var dump  ids    Important  Do not use this if you are dealing with duplicate values

User · Answer

Keep it simple      intArray   array      strArray   explode       string   foreach   strArray as  value   intArray      intval   value     Why are you looking for other ways  Looping does the job without pain  If performance is your concern  you can go with json decode     People have posted how to use that  so I am not including it here   Note  When using    operator instead of       your string values are automatically converted into numbers  e g  integer or double  if they form a valid number without quotes  For example    str    1     str    1     true but   str     1    false   Thus     may solve your problem  is efficient  but will break if you use      in comparisons

User · Answer

You can achieve this by following code    integerIDs   array map  intval   explode       string

User · Answer

If you have a multi-dimensional array  none of the previously mentioned solutions will work  Here is my solution  public function arrayValuesToInt  amp  array     if is array  array        foreach  array as  amp  arrayPiece         arrayValuesToInt  arrayPiece            else       array   intval  array          Then  just do this  arrayValuesToInt  multiDimentionalArray    This will make an array like this     quot 1 quot   quot 2 quot    quot 3 quot   quot 4 quot     look like this    1 2  3 4    This will work with any level of depth  Alternatively  you can use array walk recursive   for a shorter answer  array walk recursive  array  function  amp  value        value   intval  value

[php] Convert array values from string to int?

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