（1）线形：
'-' solid line style '--' dashed line style '-.' dash-dot line style ':' dotted line style
（2）marker类型：
'.' point marker ',' pixel marker 'o' circle marker 'v' triangle_down marker '^' triangle_up marker '<' triangle_left marker '>' triangle_right marker '1' tri_down marker '2' tri_up marker '3' tri_left marker '4' tri_right marker 's' square marker 'p' pentagon marker '*' star marker 'h' hexagon1 marker 'H' hexagon2 marker '+' plus marker 'x' x marker 'D' diamond marker 'd' thin_diamond marker '|' vline marker '_' hline marker
（3）颜色：