Como Remover Linha de CSV？

Question

Eis是一个追寻精确去除剂的linhas de um csv que contum um valor incorreto compandas。

df.head()

    YEAR    JAN     FEB     MAR     APR     MAY     JUN     JUL     AUG     SEP     OCT     NOV     DEC     D-J-F   M-A-M   J-J-A   S-O-N   metANN
0   1961    999.90  999.90  999.90  999.90  999.90  999.90  999.90  999.90  999.90  999.90  999.90  24.97   999.90  999.90  999.90  999.90  999.90
1   1962    26.07   25.97   26.07   25.77   24.47   23.37   22.47   22.47   23.37   22.97   24.67   25.18   25.67   25.44   22.77   23.67   24.39
2   1963    999.90  25.78   26.38   25.68   23.68   999.90  22.08   22.38   23.08   24.18   24.88   24.67   25.51   25.25   22.46   24.05   24.32

Desejo卸妆todas，如linhas que possuem esse。999.90alguémme ajuda parecetána cara masnãosei。