Question

有两个数据帧df1和df2。 df1中的两列是A和B。B中缺少值。对于df1中B中的丢失值，df2中有条目，其列是A和B（df2中的记录是B中缺少的记录仅df1）。我想用df2中B的对应条目替换df1中B的缺失值。

编辑：

$(document).ready(function(){

 load_business_data();

 function load_business_data()
 {
  $.ajax({
   url:"m.php",
   method:"POST",
   success:function(data)
   {
    $('#business_list').html(data);
   }
  });
 }

 $(document).on('mouseenter', '.rating', function(){
  var index = $(this).data("index");
  var business_id = $(this).data('business_id');
  remove_background(business_id);
  for(var count = 1; count<=index; count++)
  {
   $('#'+business_id+'-'+count).css('color', '#ffcc00');
  }
 });

 function remove_background(business_id)
 {
  for(var count = 1; count <= 5; count++)
  {
   $('#'+business_id+'-'+count).css('color', '#ccc');
  }
 }

 $(document).on('mouseleave', '.rating', function(){
  var index = $(this).data("index");
  var business_id = $(this).data('business_id');
  var rating = $(this).data("rating");
  remove_background(business_id);
  //alert(rating);
  for(var count = 1; count<=rating; count++)
  {
   $('#'+business_id+'-'+count).css('color', '#ffcc00');
  }
 });

 $(document).on('click', '.rating', function(){
  var index = $(this).data("index");
  var business_id = $(this).data('business_id');
var username='<?php echo $_SESSION["username"];?>';
var useremail='<?php echo $_SESSION["useremail"];?>';

  $.ajax({
   url:"insert_rating.php",
   method:"POST",
   data:{index:index, business_id:business_id, username:username, useremail:useremail},
   success:function(data)
   {
if(data == 'done')
    {
       alert("There is some problem in System");
    }
    else
    {
 load_business_data();
     alert("Dear "+username+",You have rate "+index +" out of 5");

    }
   }
  });

 });

});
</script>
here is my pdo code use to insert query
<?php

//insert_rating.php
session_start();
$connect = new PDO('mysql:host=localhost;dbname=final', 'root', '');

if(isset($_POST["index"], $_POST["business_id"], $_POST["username"], $_POST["useremail"]))
{  
 $query = "
 INSERT INTO rating(business_id, rating, username,useremail) 
 VALUES (:business_id, :rating, :username, :useremail)
 ";
  $statement = $connect->prepare($query);
      $statement->execute(
  array(
   ':business_id'  => $_POST["business_id"],
   ':rating'   => $_POST["index"],
':username'   => $_POST["username"],
':useremail'   => $_POST["useremail"],
  )
);
 $result = $statement->fetchAll();
 if(isset($result))
 {
echo 'done';

?>

所需的O / P：

df1 = pd.DataFrame({'A': [1,2,3,4,5,6,7,8], 'b': [101,123,np.nan,678,np.nan,672,np.nan,786], 'C': ['ABC', 'DER', 'ERC','DFE','HJI','JKL','SDH',np.Nan]})

df2 = pd.DataFrame({'A': [3,7], 'B': [563,785]})

Answer 1

使用pd.merge左合并df1列上的数据帧df2和A，然后使用Series.fillna填充列{{1 }} b列中的值：

结果：

df = pd.merge(df1, df2, on='A', how='left')
df['b'] = df['b'].fillna(df.pop('B'))

如何用python中其他数据框的条目替换一个数据框中的列丢失的条目？

1 个答案: