/** * lowercase letters */
        $this->store['upper_Spec'] = array( *cut* );
        /** * uppercase letters */
        $this->store['lower_Spec'] = array( *cut* );
      
                    } else {
                      $errmsg='An unknown error occured.';
                    }
                  } else {
                    $errmsg='The passwords you entered do not match';
                  }
                } else {
                  $errmsg='Password has to be at least 8 characters long.';
                }
              } else {
                $errmsg='The email you entered is already in our database.';
              }
            } else {
              $errmsg='Please enter your email address.';
            }
          } else {
            $errmsg='Please enter your first name and your last name.';
          }
        } else {
        (...)
      
        // Happy debugging, suckers
        # define true (rand() > 10)
      

Your snippets

+1

##Import files
df1=fread("Master_September 26, 2018_08.18.000.csv")
df2=fread("Master_September 26, 2018_08.18.001.csv")
df3=fread("Master_September 26, 2018_08.18.002.csv")
df4=fread("Master_September 26, 2018_08.18.003.csv")
df5=fread("Master_September 26, 2018_08.18.004.csv")
df6=fread("Master_September 26, 2018_08.18.005.csv")
df7=fread("Master_September 26, 2018_08.18.006.csv")
df8=fread("Master_September 26, 2018_08.18.007.csv")
df9=fread("Master_September 26, 2018_08.18.008.csv")
df10=fread("Master_September 26, 2018_08.18.009.csv")

##Remove duplicate column
df1=df1[,-50]
df2=df2[,-50]
df3=df3[,-50]
df4=df4[,-50]
df5=df5[,-50]
df6=df6[,-50]
df7=df7[,-50]
df8=df8[,-50]
df9=df9[,-50]
df10=df10[,-50]

##Reduce columns
df1=sqldf('select Finished,ResponseId,RecordedDate,UserLanguage,S1,S1a,S2_1,S2_2,S2_3,S2_4,S2_5,M1,M2,Country,SelectedTP,E1,E2,E2a,E2a_9_TEXT,E2b_1,E2b_2,E2b_3,E2b_4,E2b_5,E2b_6,E3_1,E3_2,E3_3,E3_4,E3_5,E3_6,E4,E1a from df1')
df2=sqldf('select Finished,ResponseId,RecordedDate,UserLanguage,S1,S1a,S2_1,S2_2,S2_3,S2_4,S2_5,M1,M2,Country,SelectedTP,E1,E2,E2a,E2a_9_TEXT,E2b_1,E2b_2,E2b_3,E2b_4,E2b_5,E2b_6,E3_1,E3_2,E3_3,E3_4,E3_5,E3_6,E4,E1a from df2')
df3=sqldf('select Finished,ResponseId,RecordedDate,UserLanguage,S1,S1a,S2_1,S2_2,S2_3,S2_4,S2_5,M1,M2,Country,SelectedTP,E1,E2,E2a,E2a_9_TEXT,E2b_1,E2b_2,E2b_3,E2b_4,E2b_5,E2b_6,E3_1,E3_2,E3_3,E3_4,E3_5,E3_6,E4,E1a from df3')
df4=sqldf('select Finished,ResponseId,RecordedDate,UserLanguage,S1,S1a,S2_1,S2_2,S2_3,S2_4,S2_5,M1,M2,Country,SelectedTP,E1,E2,E2a,E2a_9_TEXT,E2b_1,E2b_2,E2b_3,E2b_4,E2b_5,E2b_6,E3_1,E3_2,E3_3,E3_4,E3_5,E3_6,E4,E1a from df4')
df5=sqldf('select Finished,ResponseId,RecordedDate,UserLanguage,S1,S1a,S2_1,S2_2,S2_3,S2_4,S2_5,M1,M2,Country,SelectedTP,E1,E2,E2a,E2a_9_TEXT,E2b_1,E2b_2,E2b_3,E2b_4,E2b_5,E2b_6,E3_1,E3_2,E3_3,E3_4,E3_5,E3_6,E4,E1a from df5')
df6=sqldf('select Finished,ResponseId,RecordedDate,UserLanguage,S1,S1a,S2_1,S2_2,S2_3,S2_4,S2_5,M1,M2,Country,SelectedTP,E1,E2,E2a,E2a_9_TEXT,E2b_1,E2b_2,E2b_3,E2b_4,E2b_5,E2b_6,E3_1,E3_2,E3_3,E3_4,E3_5,E3_6,E4,E1a from df6')
df7=sqldf('select Finished,ResponseId,RecordedDate,UserLanguage,S1,S1a,S2_1,S2_2,S2_3,S2_4,S2_5,M1,M2,Country,SelectedTP,E1,E2,E2a,E2a_9_TEXT,E2b_1,E2b_2,E2b_3,E2b_4,E2b_5,E2b_6,E3_1,E3_2,E3_3,E3_4,E3_5,E3_6,E4,E1a from df7')
df8=sqldf('select Finished,ResponseId,RecordedDate,UserLanguage,S1,S1a,S2_1,S2_2,S2_3,S2_4,S2_5,M1,M2,Country,SelectedTP,E1,E2,E2a,E2a_9_TEXT,E2b_1,E2b_2,E2b_3,E2b_4,E2b_5,E2b_6,E3_1,E3_2,E3_3,E3_4,E3_5,E3_6,E4,E1a from df8')
df9=sqldf('select Finished,ResponseId,RecordedDate,UserLanguage,S1,S1a,S2_1,S2_2,S2_3,S2_4,S2_5,M1,M2,Country,SelectedTP,E1,E2,E2a,E2a_9_TEXT,E2b_1,E2b_2,E2b_3,E2b_4,E2b_5,E2b_6,E3_1,E3_2,E3_3,E3_4,E3_5,E3_6,E4,E1a from df9')
df10=sqldf('select Finished,ResponseId,RecordedDate,UserLanguage,S1,S1a,S2_1,S2_2,S2_3,S2_4,S2_5,M1,M2,Country,SelectedTP,E1,E2,E2a,E2a_9_TEXT,E2b_1,E2b_2,E2b_3,E2b_4,E2b_5,E2b_6,E3_1,E3_2,E3_3,E3_4,E3_5,E3_6,E4,E1a from df10')

##Append data and Output to CSV
L1 = list(df1,df2,df3,df4,df5,df6,df7,df8,df9,df10)