# Apache Pig - Eval Functions

Apache Pig provides various built-in functions namely **eval, load, store, math, string, bag** and **tuple** functions.

## Eval Functions

Given below is the list of **eval** functions provided by Apache Pig.

S.N. | Function & Description |
---|---|

1 | AVG()
To compute the average of the numerical values within a bag. |

2 | BagToString()
To concatenate the elements of a bag into a string. While concatenating, we can place a delimiter between these values (optional). |

3 | CONCAT()
To concatenate two or more expressions of same type. |

4 | COUNT()
To get the number of elements in a bag, while counting the number of tuples in a bag. |

5 | COUNT_STAR()
It is similar to the |

6 | DIFF()
To compare two bags (fields) in a tuple. |

7 | IsEmpty()
To check if a bag or map is empty. |

8 | MAX()
To calculate the highest value for a column (numeric values or chararrays) in a single-column bag. |

9 | MIN()
To get the minimum (lowest) value (numeric or chararray) for a certain column in a single-column bag. |

10 | PluckTuple()
Using the Pig Latin |

11 | SIZE()
To compute the number of elements based on any Pig data type. |

12 | SUBTRACT()
To subtract two bags. It takes two bags as inputs and returns a bag which contains the tuples of the first bag that are not in the second bag. |

13 | SUM()
To get the total of the numeric values of a column in a single-column bag. |

14 | TOKENIZE()
To split a string (which contains a group of words) in a single tuple and return a bag which contains the output of the split operation. |