Hi guys,

I have this DataFrame

```
mergiato <- data.frame(subject="" , Gender="",Weight="", Height="",Age="",test="",act="",VelInc_X_mean="",VelInc_Y_mean="",VelInc_Z_mean="", VelInc_X_SD="",VelInc_Y_SD="",VelInc_Z_SD="",VelInc_MEAN="",VelInc_SD="", OriInc_w_mean="",OriInc_w_SD="",OriInc_x_mean="",OriInc_x_SD="",OriInc_y_mean="",OriInc_y_SD="",OriInc_z_mean="",OriInc_z_SD="",OriInc_MEAN="",OriInc_SD="",Acc_X_SD="",Acc_Y_mean="",Acc_Y_SD="",Acc_Z_mean="",Acc_Z_SD="",Acc_MEAN="",Acc_SD="",Gyr_X_mean="",Gyr_X_SD="", Gyr_Y_mean="",Gyr_Y_SD="",Gyr_Z_mean="",Gyr_Z_SD="",Gyr_MEAN="",Gyr_SD="",Mag_X_mean="",Mag_X_SD="",Mag_Y_mean="",Mag_Y_SD="",Mag_Z_mean="",Mag_Z_SD="",Mag_MEAN="",Mag_SD="",Roll_mean="",Pitch_mean="",Yaw_mean="",RSSI_mean="")
```

i want to remove some columns. I did it in this way :

```
mergiato$VelInc_X_mean <- NULL
mergiato$VelInc_Y_mean <- NULL
mergiato$VelInc_Z_mean <- NULL
mergiato$VelInc_X_SD <- NULL
mergiato$VelInc_Y_SD <- NULL
mergiato$VelInc_Z_SD <- NULL
mergiato$OriInc_w_mean <- NULL
mergiato$OriInc_x_mean <- NULL
mergiato$OriInc_y_mean <- NULL
mergiato$OriInc_z_mean <- NULL
mergiato$OriInc_w_SD <- NULL
mergiato$OriInc_x_SD <- NULL
mergiato$OriInc_y_SD <- NULL
mergiato$OriInc_z_SD <- NULL
mergiato$Acc_X_mean <- NULL
mergiato$Acc_Y_mean <- NULL
mergiato$Acc_Z_mean <- NULL
mergiato$Acc_X_SD <- NULL
mergiato$Acc_Y_SD <- NULL
mergiato$Acc_Z_SD <- NULL
mergiato$Mag_X_mean <- NULL
mergiato$Mag_Y_mean <- NULL
mergiato$Mag_Z_mean <- NULL
mergiato$Mag_X_SD <- NULL
mergiato$Mag_Y_SD <- NULL
mergiato$Mag_Z_SD <- NULL
mergiato$Gyr_X_mean <- NULL
mergiato$Gyr_Y_mean <- NULL
mergiato$Gyr_Z_mean <- NULL
mergiato$Gyr_X_SD <- NULL
mergiato$Gyr_Y_SD <- NULL
mergiato$Gyr_Z_SD <- NULL
```

**it works**, and I get what I wanted, **but** I would like to write it in a more "beautiful" way. and even more efficient, because if for example I had a dataframe with 1000 columns to delete, I would have to write 1000 lines to delete them

I add something that might be useful.

I think you could make a command like:

If in the column name, there is the character: *" x" or "y" or "z"*, (both uppercase and lowercase) deletes the column.