orignla array:
Array
(
    [1] => twentieth-century-essays
    [2] => social-problems-essays
    [3] => federal-government-essays
    [4] => justice-essays
    [5] => courts-essays
    [6] => law-essays
    [7] => politics-essays
    [8] => society-essays
    [9] => economy-essays
    [10] => constitution-essays
    [11] => authority-essays
    [12] => boat-essays
    [13] => wisdom-essays
    [14] => activism-essays
    [15] => mcgraw-hill-essays
    [16] => police-essays
)

remove array:
Array
(
    [1] => twentieth-century-essays
    [2] => social-problems-essays
    [3] => federal-government-essays
    [4] => justice-essays
    [5] => courts-essays
    [6] => law-essays
    [7] => politics-essays
    [8] => society-essays
    [9] => economy-essays
    [10] => constitution-essays
    [11] => authority-essays
    [12] => boat-essays
    [13] => wisdom-essays
    [14] => activism-essays
    [15] => mcgraw-hill-essays
    [16] => police-essays
)