PHP JSON To CSV File (Simple Examples)

Welcome to a tutorial on how to write JSON data to a CSV file in PHP. So you are working on a project that maybe received JSON data from an API and need to write that to a CSV file?

Just how do we do that exactly? Read on for the examples!

 

 

TLDR – QUICK SLIDES

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TABLE OF CONTENTS

 

 

 

EXAMPLE 1) NESTED JSON ARRAY

[["Joe Doe","joe@doe.com"],["Jon Doe","jon@doe.com"],["Joy Doe","joy@doe.com"]]

<?php
// (A) JSON DATA TO ARRAY
$data = file_get_contents("1a-data.json");
$data = json_decode($data);
print_r($data);
 
// (B) WRITE TO CSV
$handle = fopen("demoA.csv", "w");
if ($handle === false) { exit("Error creating CSV file"); }
foreach ($data as $row) { fputcsv($handle, $row); }
fclose($handle);
echo "OK";

For those who are lost, $data is a nested array in the format of [[NAME, EMAIL], [NAME, EMAIL], ...]. Since this is already “nicely formatted”, all we have to do is loop through the entries and write to the CSV file.

 

 

EXAMPLE 2) FLAT ARRAY

["Joe Doe","joe@doe.com","Jon Doe","jon@doe.com","Joy Doe","joy@doe.com"]

<?php
// (A) JSON DATA TO ARRAY
$data = file_get_contents("2a-data.json");
$data = json_decode($data);
print_r($data);
 
// (B) WRITE TO CSV
$handle = fopen("demoB.csv", "w");
if ($handle === false) { exit("Error creating CSV file"); }
$i = 0; $j = [];
foreach ($data as $row) {
  $j[] = $row; $i++;
  if ($i==2) {
    fputcsv($handle, $j);
    $i = 0; $j = [];
  }
}
fclose($handle);
echo "OK";

Now, $data in this example is now a flat array in the format of [NAME, EMAIL, NAME, EMAIL, ...]. Yep, since someone did not “nicely format” the data, we have to do it manually. What this example does –

• Loop through $data, collect the current value into $j and increment $i.
• When $i==2, we write $j as a row into the CSV file.
• Rinse-and-repeat until there are no more entires.

 

 

EXAMPLE 3) ASSOCIATIVE ARRAY

{"NAME":["Joe Doe","Jon Doe","Joy Doe"],"EMAIL":["joe@doe.com","jon@doe.com","joy@doe.com"]}

<?php
// (A) JSON DATA TO ARRAY
$data = file_get_contents("3a-data.json");
$data = json_decode($data, true);
print_r($data);
 
// (B) EXTRACT SOME DATA
$keys = array_keys($data);
$entries = count($data[$keys[0]]);
 
// (C) WRITE TO CSV
// (C1) OPEN FILE
$handle = fopen("demoC.csv", "w");
if ($handle === false) { exit("Error creating CSV file"); }
 
// (C2) FIRST ROW - HEADERS
fputcsv($handle, $keys);
 
// (C3) OTHER ROWS - VALUES
for ($i=0; $i<$entries; $i++) {
  $row = [];
  foreach ($keys as $k) { $row[] = $data[$k][$i]; }
  fputcsv($handle, $row);
}
 
// (C4) DONE
fclose($handle);
echo "OK";

In this example, $data is a little funky, in the format of ["NAME": ARRAY OF NAMES, "EMAIL": ARRAY OF EMAILS]. A little more challenging, but trace through and it should explain itself:

• Extract the keys of $data and use them as the first row of the CSV file.
• Loop through the rest of the entries and append to the CSV accordingly.

 

 

EXAMPLE 4) MORE ASSOCIATIVE ARRAY

[{"NAME":"Joe Doe","EMAIL":"joe@doe.com"},{"NAME":"Jon Doe","EMAIL":"jon@doe.com"},{"NAME":"Joy Doe","EMAIL":"joy@doe.com"}]

<?php
// (A) JSON DATA TO ARRAY
$data = file_get_contents("4a-data.json");
$data = json_decode($data, true);
print_r($data);
 
// (B) EXTRACT KEYS
$keys = array_keys($data[0]);

// (C) WRITE TO CSV
// (C1) OPEN FILE
$handle = fopen("demoD.csv", "w");
if ($handle === false) { exit("Error creating CSV file"); }
 
// (C2) FIRST ROW - HEADERS
fputcsv($handle, $keys);
 
// (C3) OTHER ROWS - VALUES
foreach ($data as $row) {
  fputcsv($handle, array_values($row));
}

// (C4) DONE
fclose($handle);
echo "OK";

Finally, $data for this one is in the format of [["EMAIL":EMAIL, "NAME":NAME], ["EMAIL":EMAIL, "NAME":NAME], ...]. A lot easier to work with than the previous example.

• Extract the array keys from $data[0], write to the first row of the CSV file.
• Loop through $data, extract the values only and write to the CSV file.

The end!

 

 

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EXAMPLE CODE DOWNLOAD

Click here for the source code on GitHub gist, just click on “download zip” or do a git clone. I have released it under the MIT license, so feel free to build on top of it or use it in your own project.

 

 

 

LINKS & REFERENCES

• Ways To Read Files In PHP – Code Boxx
• PHP Write & Apped Files – Code Boxx
• fputcsv – Official PHP Manual

 

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