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https://github.com/awdeorio/csvstream
An easy-to-use CSV file parser for C++
https://github.com/awdeorio/csvstream
Last synced: 3 months ago
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An easy-to-use CSV file parser for C++
- Host: GitHub
- URL: https://github.com/awdeorio/csvstream
- Owner: awdeorio
- License: mit
- Created: 2016-06-17T12:34:49.000Z (over 8 years ago)
- Default Branch: main
- Last Pushed: 2024-04-19T12:54:30.000Z (7 months ago)
- Last Synced: 2024-05-01T00:31:59.557Z (6 months ago)
- Language: C++
- Size: 134 KB
- Stars: 50
- Watchers: 3
- Forks: 18
- Open Issues: 4
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
- AwesomeCppGameDev - csvstream - to-use CSV file parser for C++ (C++)
README
csvstream
=========
[](https://travis-ci.com/awdeorio/csvstream)
An easy-to-use CSV file parser for C++
Andrew DeOrio
http://andrewdeorio.com
**Table of Contents**
- [Quick start](#quick-start)
- [Example 1: Read one column](#example-1-read-one-column)
- [Example 2: Read each row and each column with nested loops](#example-2-read-each-row-and-each-column-with-nested-loops)
- [Example 3: Maintaining order of columns in each row](#example-3-maintaining-order-of-columns-in-each-row)
- [Changing the delimiter](#changing-the-delimiter)
- [Allow too many or too few values in a row](#allow-too-many-or-too-few-values-in-a-row)
- [Error handling](#error-handling)
## Quick start
```console
$ git clone https://github.com/awdeorio/csvstream.git
$ cd csvstream/
$ make test
```
## Example 1: Read one column
This example reads one column from a CSV file.
```c++
// example1.cpp
#include "csvstream.hpp"
#include
#include
#include
using namespace std;
int main() {
// Open file
csvstream csvin("input.csv");
// Rows have key = column name, value = cell datum
map row;
// Extract the "animal" column
while (csvin >> row) {
cout << row["animal"] << "\n";
}
}
```
Input
```console
$ cat input.csv
name,animal
Fergie,horse
Myrtle II,chicken
Oscar,cat
```
Compile
```console
$ make example1
# OR
$ g++ -std=c++11 example1.cpp -o example1
```
Output
```console
$ ./example1
horse
chicken
cat
```
## Example 2: Read each row and each column with nested loops
This example has an outer loop for each row and an inner loop for each column.
```c++
//example2.cpp
#include "csvstream.hpp"
#include
#include
#include
using namespace std;
int main() {
// Open file
csvstream csvin("input.csv");
// A row is a map, key = column name, value = datum
map row;
// Read file
while (csvin >> row) {
cout << "row:" << "\n";
for (auto &col:row) {
const string &column_name = col.first;
const string &datum = col.second;
cout << " " << column_name << ": " << datum << "\n";
}
}
}
```
Input
```console
$ cat input.csv
name,animal
Fergie,horse
Myrtle II,chicken
Oscar,cat
```
Compile
```console
$ make example2
# OR
$ g++ -std=c++11 example2.cpp -o example2
```
Output. Notice output order within each row is `animal` followed by `name`. This is because iterating over a `map` yields items in sorted order by key.
```console
$ ./example2
row:
animal: horse
name: Fergie
row:
animal: chicken
name: Myrtle II
row:
animal: cat
name: Oscar
```
## Example 3: Maintaining order of columns in each row
This example uses a vector-of-pair to maintain the order of values read from each row.
```c++
// example3.cpp
#include "csvstream.hpp"
#include
#include
#include
#include
using namespace std;
int main() {
// Open file
csvstream csvin("input.csv");
// A row is a vector>
// key = column name, value = cell datum
vector> row;
// Read file
while (csvin >> row) {
cout << "row:" << "\n";
for (unsigned int i=0; i < row.size(); ++i) {
const string &column_name = row[i].first;
const string &datum = row[i].second;
cout << " " << column_name << ": " << datum << "\n";
}
}
}
```
Input
```console
$ cat input.csv
name,animal
Fergie,horse
Myrtle II,chicken
Oscar,cat
```
Compile
```console
$ make example3
# OR
$ g++ -std=c++11 example3.cpp -o example3
```
Output. Notice output order within each row is `name` followed by `animal`. This is the order that the columns appear in the CSV file.
```console
$ ./example3
row:
name: Fergie
animal: horse
row:
name: Myrtle II
animal: chicken
row:
name: Oscar
animal: cat
```
## Changing the delimiter
By default, values in a row are delimited by a comma `,`. Change the delimiter with the `delimiter` constructor parameter.
This example changes the delimiter to the `|` character.
```c++
csvstream csvin("input.csv", '|');
```
## Allow too many or too few values in a row
By default, if a row has too many or too few values, csvstream raises and exception. With strict mode disabled, it will ignore extra values and set missing values to empty string. You must specify a delimiter when using strict mode.
```c++
csvstream csvin("input.csv", ',', false);
```
## Error handling
If an error occurs, `csvstream` functions throw a `cstream_exception` . For example:
```c++
// example4.cpp
#include "csvstream.hpp"
#include
#include
#include
using namespace std;
int main() {
// Open file
string filename = "input.csv";
try {
csvstream csvin(filename);
map row;
while (csvin >> row) {
cout << row["animal"] << "\n";
}
} catch(const csvstream_exception &e) {
cerr << "Error: " << e.what() << "\n";
return 1;
}
}
```