Returns the integer part of a value.

iPart(*value*)

Press:

- MATH to access the math menu.
- RIGHT to access the NUM submenu
- 3 to select iPart(, or use arrows.

TI-83/84/+/SE/CE

1 byte

`iPart( value)` returns the integer part of

*value*, and extends to complex numbers, lists, and matrices.

```
iPart(5.32)
5
iPart(4/5)
0
iPart(‾5.32)
‾5
iPart(‾4/5)
0
```

`iPart` is sometimes used with it's corresponding partner `fPart`. While `iPart` trims off the part *before* the decimal point, `fPart` trims off the part *after* it.

The difference between `iPart(` and `int(` is subtle; while `iPart(` always truncates its parameters, simply removing the integer part, `int(` always rounds down. This means that they return the same answers for positive numbers, but `int(` will return an answer 1 less than `iPart(` for (non-integer) negative numbers. For example, `iPart(-5.32)` is -5, while `int(-5.32)` is -6.

In this case of positive values, though, the decision to use `iPart(` or `int(` is mostly a matter of preference - some people only use `int(` because it is shorter, some people use `iPart(` when there is a corresponding `fPart(` taken. However, see the Command Timings section.

# Watch Out For Precision Issues

```
1/3*3→X // X is expected to be 1
X // Displays 1, but is actually 0.99999999999999 in memory
iPart(X) // Displays 0
fPart(X) // Displays 1, but is actually 0.99999999999999 in memory
```

Somewhat unintuitively, the code above displays the results 1, 0 and 1. This is due to the calculator storing values to 14 digits of precision, but rounding the value to 10 digits to fit on the home screen.

*Tip:* If you enter a value in the list editor screen, you will be able to see all 14 digits of precision. This can help you troubleshoot issues like these.

One workaround is to round the numbers prior to calling `iPart()` or `fPart()`, if you don't mind the slight loss in precision from 14 significant digits to 9 decimal places:

```
1/3*3→X
iPart(round(X,9)) // Displays the expected result 1
fPart(round(X,9)) // Displays the expected result 0
```

(The parameter 9 is not technically required here since 9 is the default, but is shown for clarity and in case you want to customize the level of precision.)

# Advanced Uses

`iPart(`, along with `fPart(` and `int(`, can be used for integer compression.

# Command Timings

The following table compares the speeds of `int(` and `iPart(`. Each command was timed over 2000 iterations to find a noticeable difference.

Format | Bars | Pixels | Total |
---|---|---|---|

iPart(1 | 10 | 1 | 81 |

iPart(1.643759 | 10 | 1 | 81 |

int(1 | 8 | 7 | 71 |

int(1.643759 | 10 | 2 | 82 |

Conclusion: With 5 or fewer decimal places, you should consider using `int(` because of its speed, but with more decimals, `iPart(` remains constant to eventually beat out its counterpart.

# Related Commands

# See Also

.