## Parsed with column specification:
## cols(
##   .default = col_character(),
##   ID = col_integer(),
##   `HW1 (128208)` = col_double(),
##   `HW2 (132130)` = col_double(),
##   `HW3 (133849)` = col_double(),
##   `HW4 (134896)` = col_double(),
##   `HW5 (135018)` = col_double(),
##   `HW6 (136778)` = col_double(),
##   `HW7 (138363)` = col_double(),
##   `HW8 (138364)` = col_double(),
##   `HW9 (138365)` = col_double(),
##   `HW10 (138366)` = col_double(),
##   `HW11 (138367)` = col_double(),
##   `HW12 (138368)` = col_double(),
##   `HW13 (138369)` = col_double()
## )
## See spec(...) for full column specifications.
#str(grades, list.len=nrow(grades))
grades<-as.data.frame(grades)
grades
##           id letter
## 1   90712470      A
## 2   10834945      A
## 3   40958959      A
## 4   71270599      A
## 5   30594673      A
## 6   11298397      A
## 7   71130053      A
## 8   70958422      A
## 9   21131253      A
## 10  91126001      A
## 11  60958130      A
## 12  61299734      A
## 13  30833058      A
## 14  61301739      A
## 15  11131638      A
## 16  80987579      A
## 17  10737923     A-
## 18  91301733     A-
## 19  31126037     A-
## 20  11172695     A-
## 21  91262886     A-
## 22  90920596     A-
## 23  81272085     A-
## 24  50917975     A-
## 25  61288554     A-
## 26  11289207     A-
## 27  81288763     A-
## 28  51241371     A-
## 29  21263052     A-
## 30  90967568     A-
## 31  21265586     A-
## 32  11290019     A-
## 33  11300626     A-
## 34  80640501     A-
## 35  20964944     A-
## 36  90901915     A-
## 37  11289673     A-
## 38  80969260     A-
## 39  50957640     A-
## 40  21127647     A-
## 41  41123540     A-
## 42  30832957     A-
## 43  10958768     B+
## 44  21263427     B+
## 45  41262737     B+
## 46  91126907     B+
## 47  90737937     B+
## 48  31266580     B+
## 49  40929371     B+
## 50  91295954     B+
## 51  81288992     B+
## 52  21127639     B+
## 53  81289638     B+
## 54  70975270     B+
## 55  71249921     B+
## 56  90741373     B+
## 57  71265722     B+
## 58  61262857     B+
## 59  20712198     B+
## 60  21288616     B+
## 61  20933658     B+
## 62  11268463     B+
## 63  81289352     B+
## 64  21289108      B
## 65  80978898      B
## 66  41292741      B
## 67  81301905      B
## 68  81301344      B
## 69  60972982      B
## 70  21289361      B
## 71  51272854      B
## 72  71267490      B
## 73  10885914      B
## 74  20619236      B
## 75  41128364      B
## 76  41262974      B
## 77  71299430      B
## 78  10714796      B
## 79  91126192      B
## 80  11291341      B
## 81  21289612      B
## 82  40763759      B
## 83  71301656      B
## 84  51290356      B
## 85  81300399     B-
## 86  31123178     B-
## 87  90679309     B-
## 88  40452729     B-
## 89  21269956     B-
## 90  80790716     B-
## 91  30643208     B-
## 92  60874891     B-
## 93  91301717     B-
## 94  80756313     B-
## 95  70888335     B-
## 96  31128390     C+
## 97  51275314     C+
## 98  41300868     C+
## 99  21267813     C+
## 100 31302161      C
## 101 91271214      C
## 102 11122914      C
## 103 71298396      C
## 104 60972273      C