Replace
Replace
Replace[ list, new, positions ] replaces the elements at the given positions of a list.
Usages
Replace[ list, {new1, new2, ...}, {i1, i2, ...} ]
Returns a copy of list in which the element at position i1 is replaced by new1, the element at position i2 by new2, and so on. Both lists must have the same length.
| Example | in | out |
|---|---|---|
| Replace the second element. | Replace[ {a, b, c}, {b2}, {2} ] |
{a, b2, c} |
| Replace the first and third element. | Replace[ {a, b, c}, {x, z}, {1, 3} ] |
{x, b, z} |
| Replace a term of a sum. | Replace[ 2x + 3y, {5z}, {2} ] |
2x+5z |
Replace[ list, x -> expr, {i1, i2, ...} ]
With a mapping, the mapping is applied to the elements at the given positions.
| Example | in | out |
|---|---|---|
| Square the second element. | Replace[ {a, b, c}, x -> x^2, {2} ] |
{a, b^2, c} |
Multiply the first and third element by 10. |
Replace[ {1, 2, 3}, x -> CalcTimes[x, 10], {1, 3} ] |
{10, 2, 30} |
Details
| Invalid input | Result |
|---|---|
Replace[ {a, b, c}, {x, y}, {2} ] |
Error: the length of the 2nd and 3rd arguments should be equal |
Replace[ {a, b, c}, {x}, {5} ] |
Error: invalid position |
Replace[ {a, b, c}, {x} ] |
Error: the number of arguments should be three |
See also: RemoveI, Substitute, Map, Elm ([[ ]])