First read in the Data by adding the Data into my GitHub repository, and finding the column names in the data dictionary.

mush1 <-   read.csv("https://raw.githubusercontent.com/Luz917/mushroomdataset/master/agaricus-lepiota.data.txt", stringsAsFactors = FALSE)
colnames(mush1) <- c("Attribute-information","cap-shape","cap-surface", "cap-color","bruises","odor","gill-attachment", "gill-spacing",     "gill-size","gill-color","stalk-shape","stalk-root","stalk-surface-above-ring","stalk-surface-below-ring","stalk-color-above-ring",  "stalk-color-below-ring", "veil-type", "veil-color" , "ring-number", "ring-type", "spore-print-color", "population", "habitat")
str(mush1)
## 'data.frame':    8123 obs. of  23 variables:
##  $ Attribute-information   : chr  "e" "e" "p" "e" ...
##  $ cap-shape               : chr  "x" "b" "x" "x" ...
##  $ cap-surface             : chr  "s" "s" "y" "s" ...
##  $ cap-color               : chr  "y" "w" "w" "g" ...
##  $ bruises                 : chr  "t" "t" "t" "f" ...
##  $ odor                    : chr  "a" "l" "p" "n" ...
##  $ gill-attachment         : chr  "f" "f" "f" "f" ...
##  $ gill-spacing            : chr  "c" "c" "c" "w" ...
##  $ gill-size               : chr  "b" "b" "n" "b" ...
##  $ gill-color              : chr  "k" "n" "n" "k" ...
##  $ stalk-shape             : chr  "e" "e" "e" "t" ...
##  $ stalk-root              : chr  "c" "c" "e" "e" ...
##  $ stalk-surface-above-ring: chr  "s" "s" "s" "s" ...
##  $ stalk-surface-below-ring: chr  "s" "s" "s" "s" ...
##  $ stalk-color-above-ring  : chr  "w" "w" "w" "w" ...
##  $ stalk-color-below-ring  : chr  "w" "w" "w" "w" ...
##  $ veil-type               : chr  "p" "p" "p" "p" ...
##  $ veil-color              : chr  "w" "w" "w" "w" ...
##  $ ring-number             : chr  "o" "o" "o" "o" ...
##  $ ring-type               : chr  "p" "p" "p" "e" ...
##  $ spore-print-color       : chr  "n" "n" "k" "n" ...
##  $ population              : chr  "n" "n" "s" "a" ...
##  $ habitat                 : chr  "g" "m" "u" "g" ...
dim(mush1)
## [1] 8123   23

Subsetting the Mushroom Data

mush2 <- mush1[c(1:100),c(1,5,9,11,17)]
mush2
##     Attribute-information bruises gill-size stalk-shape veil-type
## 1                       e       t         b           e         p
## 2                       e       t         b           e         p
## 3                       p       t         n           e         p
## 4                       e       f         b           t         p
## 5                       e       t         b           e         p
## 6                       e       t         b           e         p
## 7                       e       t         b           e         p
## 8                       p       t         n           e         p
## 9                       e       t         b           e         p
## 10                      e       t         b           e         p
## 11                      e       t         b           e         p
## 12                      e       t         b           e         p
## 13                      p       t         n           e         p
## 14                      e       f         b           t         p
## 15                      e       f         n           e         p
## 16                      e       f         b           t         p
## 17                      p       t         n           e         p
## 18                      p       t         n           e         p
## 19                      p       t         n           e         p
## 20                      e       t         b           e         p
## 21                      p       t         n           e         p
## 22                      e       t         b           e         p
## 23                      e       t         b           e         p
## 24                      e       t         b           e         p
## 25                      p       t         n           e         p
## 26                      e       t         b           e         p
## 27                      e       t         b           e         p
## 28                      e       f         n           e         p
## 29                      e       t         n           t         p
## 30                      e       t         b           e         p
## 31                      p       t         n           e         p
## 32                      e       t         b           e         p
## 33                      e       t         b           e         p
## 34                      e       t         b           e         p
## 35                      e       t         n           t         p
## 36                      e       f         n           e         p
## 37                      p       t         n           e         p
## 38                      e       t         n           t         p
## 39                      e       t         b           e         p
## 40                      e       t         b           e         p
## 41                      e       t         b           e         p
## 42                      e       f         n           e         p
## 43                      p       t         n           e         p
## 44                      e       t         b           e         p
## 45                      e       t         b           e         p
## 46                      e       t         b           e         p
## 47                      e       t         b           e         p
## 48                      e       t         b           e         p
## 49                      e       t         b           e         p
## 50                      e       t         b           e         p
## 51                      e       t         b           e         p
## 52                      e       t         b           e         p
## 53                      p       t         n           e         p
## 54                      p       t         n           e         p
## 55                      e       t         b           e         p
## 56                      e       f         b           t         p
## 57                      e       t         b           e         p
## 58                      e       t         b           e         p
## 59                      e       t         b           e         p
## 60                      e       f         n           e         p
## 61                      e       t         b           e         p
## 62                      e       t         b           e         p
## 63                      e       t         b           e         p
## 64                      e       t         b           e         p
## 65                      e       f         b           t         p
## 66                      e       t         b           e         p
## 67                      e       t         b           e         p
## 68                      e       t         b           e         p
## 69                      e       f         n           e         p
## 70                      e       t         n           t         p
## 71                      e       t         b           e         p
## 72                      e       t         n           t         p
## 73                      e       t         b           e         p
## 74                      e       t         b           e         p
## 75                      e       t         n           t         p
## 76                      e       t         n           t         p
## 77                      e       t         b           e         p
## 78                      p       t         n           e         p
## 79                      e       t         b           e         p
## 80                      e       f         b           t         p
## 81                      p       t         n           e         p
## 82                      e       f         n           e         p
## 83                      e       f         b           t         p
## 84                      e       t         b           e         p
## 85                      e       f         b           t         p
## 86                      e       t         b           e         p
## 87                      e       t         b           e         p
## 88                      e       t         b           e         p
## 89                      e       f         n           e         p
## 90                      e       f         n           e         p
## 91                      e       t         b           e         p
## 92                      e       t         b           e         p
## 93                      e       t         b           e         p
## 94                      e       f         b           t         p
## 95                      e       t         b           e         p
## 96                      e       t         b           e         p
## 97                      e       t         b           e         p
## 98                      e       t         b           e         p
## 99                      e       t         b           e         p
## 100                     e       f         b           t         p

Change the Column Names of the new data frame

colnames(mush2)<- c("PoisonousOrEdible","DoesItBruise","ShapOfGill", "ShapeOfStalk", "TypeOfVeil")
mush2
##     PoisonousOrEdible DoesItBruise ShapOfGill ShapeOfStalk TypeOfVeil
## 1                   e            t          b            e          p
## 2                   e            t          b            e          p
## 3                   p            t          n            e          p
## 4                   e            f          b            t          p
## 5                   e            t          b            e          p
## 6                   e            t          b            e          p
## 7                   e            t          b            e          p
## 8                   p            t          n            e          p
## 9                   e            t          b            e          p
## 10                  e            t          b            e          p
## 11                  e            t          b            e          p
## 12                  e            t          b            e          p
## 13                  p            t          n            e          p
## 14                  e            f          b            t          p
## 15                  e            f          n            e          p
## 16                  e            f          b            t          p
## 17                  p            t          n            e          p
## 18                  p            t          n            e          p
## 19                  p            t          n            e          p
## 20                  e            t          b            e          p
## 21                  p            t          n            e          p
## 22                  e            t          b            e          p
## 23                  e            t          b            e          p
## 24                  e            t          b            e          p
## 25                  p            t          n            e          p
## 26                  e            t          b            e          p
## 27                  e            t          b            e          p
## 28                  e            f          n            e          p
## 29                  e            t          n            t          p
## 30                  e            t          b            e          p
## 31                  p            t          n            e          p
## 32                  e            t          b            e          p
## 33                  e            t          b            e          p
## 34                  e            t          b            e          p
## 35                  e            t          n            t          p
## 36                  e            f          n            e          p
## 37                  p            t          n            e          p
## 38                  e            t          n            t          p
## 39                  e            t          b            e          p
## 40                  e            t          b            e          p
## 41                  e            t          b            e          p
## 42                  e            f          n            e          p
## 43                  p            t          n            e          p
## 44                  e            t          b            e          p
## 45                  e            t          b            e          p
## 46                  e            t          b            e          p
## 47                  e            t          b            e          p
## 48                  e            t          b            e          p
## 49                  e            t          b            e          p
## 50                  e            t          b            e          p
## 51                  e            t          b            e          p
## 52                  e            t          b            e          p
## 53                  p            t          n            e          p
## 54                  p            t          n            e          p
## 55                  e            t          b            e          p
## 56                  e            f          b            t          p
## 57                  e            t          b            e          p
## 58                  e            t          b            e          p
## 59                  e            t          b            e          p
## 60                  e            f          n            e          p
## 61                  e            t          b            e          p
## 62                  e            t          b            e          p
## 63                  e            t          b            e          p
## 64                  e            t          b            e          p
## 65                  e            f          b            t          p
## 66                  e            t          b            e          p
## 67                  e            t          b            e          p
## 68                  e            t          b            e          p
## 69                  e            f          n            e          p
## 70                  e            t          n            t          p
## 71                  e            t          b            e          p
## 72                  e            t          n            t          p
## 73                  e            t          b            e          p
## 74                  e            t          b            e          p
## 75                  e            t          n            t          p
## 76                  e            t          n            t          p
## 77                  e            t          b            e          p
## 78                  p            t          n            e          p
## 79                  e            t          b            e          p
## 80                  e            f          b            t          p
## 81                  p            t          n            e          p
## 82                  e            f          n            e          p
## 83                  e            f          b            t          p
## 84                  e            t          b            e          p
## 85                  e            f          b            t          p
## 86                  e            t          b            e          p
## 87                  e            t          b            e          p
## 88                  e            t          b            e          p
## 89                  e            f          n            e          p
## 90                  e            f          n            e          p
## 91                  e            t          b            e          p
## 92                  e            t          b            e          p
## 93                  e            t          b            e          p
## 94                  e            f          b            t          p
## 95                  e            t          b            e          p
## 96                  e            t          b            e          p
## 97                  e            t          b            e          p
## 98                  e            t          b            e          p
## 99                  e            t          b            e          p
## 100                 e            f          b            t          p

Changing the values in the rows

require(plyr)
## Loading required package: plyr
mush2$PoisonousOrEdible <-revalue(mush2$PoisonousOrEdible,c("e"="edible" , "p"="poisonous"))
mush2$DoesItBruise <-revalue(mush2$DoesItBruise,c("t"="true", "f"="false"))
mush2$ShapOfGill <-revalue(mush2$ShapOfGill,c("b"="broad", "n"= "narrow"))
mush2$ShapeOfStalk <-revalue(mush2$ShapeOfStalk,c("e"="enlarging", "t"= "tapering")) 
mush2$TypeOfVeil <-revalue(mush2$TypeOfVeil,c("p" = "partial" , "u" = "universal"))
## The following `from` values were not present in `x`: u
mush2
##     PoisonousOrEdible DoesItBruise ShapOfGill ShapeOfStalk TypeOfVeil
## 1              edible         true      broad    enlarging    partial
## 2              edible         true      broad    enlarging    partial
## 3           poisonous         true     narrow    enlarging    partial
## 4              edible        false      broad     tapering    partial
## 5              edible         true      broad    enlarging    partial
## 6              edible         true      broad    enlarging    partial
## 7              edible         true      broad    enlarging    partial
## 8           poisonous         true     narrow    enlarging    partial
## 9              edible         true      broad    enlarging    partial
## 10             edible         true      broad    enlarging    partial
## 11             edible         true      broad    enlarging    partial
## 12             edible         true      broad    enlarging    partial
## 13          poisonous         true     narrow    enlarging    partial
## 14             edible        false      broad     tapering    partial
## 15             edible        false     narrow    enlarging    partial
## 16             edible        false      broad     tapering    partial
## 17          poisonous         true     narrow    enlarging    partial
## 18          poisonous         true     narrow    enlarging    partial
## 19          poisonous         true     narrow    enlarging    partial
## 20             edible         true      broad    enlarging    partial
## 21          poisonous         true     narrow    enlarging    partial
## 22             edible         true      broad    enlarging    partial
## 23             edible         true      broad    enlarging    partial
## 24             edible         true      broad    enlarging    partial
## 25          poisonous         true     narrow    enlarging    partial
## 26             edible         true      broad    enlarging    partial
## 27             edible         true      broad    enlarging    partial
## 28             edible        false     narrow    enlarging    partial
## 29             edible         true     narrow     tapering    partial
## 30             edible         true      broad    enlarging    partial
## 31          poisonous         true     narrow    enlarging    partial
## 32             edible         true      broad    enlarging    partial
## 33             edible         true      broad    enlarging    partial
## 34             edible         true      broad    enlarging    partial
## 35             edible         true     narrow     tapering    partial
## 36             edible        false     narrow    enlarging    partial
## 37          poisonous         true     narrow    enlarging    partial
## 38             edible         true     narrow     tapering    partial
## 39             edible         true      broad    enlarging    partial
## 40             edible         true      broad    enlarging    partial
## 41             edible         true      broad    enlarging    partial
## 42             edible        false     narrow    enlarging    partial
## 43          poisonous         true     narrow    enlarging    partial
## 44             edible         true      broad    enlarging    partial
## 45             edible         true      broad    enlarging    partial
## 46             edible         true      broad    enlarging    partial
## 47             edible         true      broad    enlarging    partial
## 48             edible         true      broad    enlarging    partial
## 49             edible         true      broad    enlarging    partial
## 50             edible         true      broad    enlarging    partial
## 51             edible         true      broad    enlarging    partial
## 52             edible         true      broad    enlarging    partial
## 53          poisonous         true     narrow    enlarging    partial
## 54          poisonous         true     narrow    enlarging    partial
## 55             edible         true      broad    enlarging    partial
## 56             edible        false      broad     tapering    partial
## 57             edible         true      broad    enlarging    partial
## 58             edible         true      broad    enlarging    partial
## 59             edible         true      broad    enlarging    partial
## 60             edible        false     narrow    enlarging    partial
## 61             edible         true      broad    enlarging    partial
## 62             edible         true      broad    enlarging    partial
## 63             edible         true      broad    enlarging    partial
## 64             edible         true      broad    enlarging    partial
## 65             edible        false      broad     tapering    partial
## 66             edible         true      broad    enlarging    partial
## 67             edible         true      broad    enlarging    partial
## 68             edible         true      broad    enlarging    partial
## 69             edible        false     narrow    enlarging    partial
## 70             edible         true     narrow     tapering    partial
## 71             edible         true      broad    enlarging    partial
## 72             edible         true     narrow     tapering    partial
## 73             edible         true      broad    enlarging    partial
## 74             edible         true      broad    enlarging    partial
## 75             edible         true     narrow     tapering    partial
## 76             edible         true     narrow     tapering    partial
## 77             edible         true      broad    enlarging    partial
## 78          poisonous         true     narrow    enlarging    partial
## 79             edible         true      broad    enlarging    partial
## 80             edible        false      broad     tapering    partial
## 81          poisonous         true     narrow    enlarging    partial
## 82             edible        false     narrow    enlarging    partial
## 83             edible        false      broad     tapering    partial
## 84             edible         true      broad    enlarging    partial
## 85             edible        false      broad     tapering    partial
## 86             edible         true      broad    enlarging    partial
## 87             edible         true      broad    enlarging    partial
## 88             edible         true      broad    enlarging    partial
## 89             edible        false     narrow    enlarging    partial
## 90             edible        false     narrow    enlarging    partial
## 91             edible         true      broad    enlarging    partial
## 92             edible         true      broad    enlarging    partial
## 93             edible         true      broad    enlarging    partial
## 94             edible        false      broad     tapering    partial
## 95             edible         true      broad    enlarging    partial
## 96             edible         true      broad    enlarging    partial
## 97             edible         true      broad    enlarging    partial
## 98             edible         true      broad    enlarging    partial
## 99             edible         true      broad    enlarging    partial
## 100            edible        false      broad     tapering    partial

Original found in StackOverflow for changing values in the rows

library(plyr) junk\(nm <- revalue(junk\)nm, c(“B”=“b”))

I figured if this changes one value in the row for that column, that you can change multiple rowa within the column by using the comma between each value you want to change.