but here we have small problem in that some of the meats above are capitalized and others are not thuswe also need to convert each value to lower casein [ ]data['animal'data['food'map(str lowermap(meat_to_animalin [ ]data out[ ]food bacon pulled pork bacon pastrami corned beef bacon pastrami honey ham nova lox ounces animal pig pig pig cow cow pig cow pig salmon we could also have passed function that does all the workin [ ]data['food'map(lambda xmeat_to_animal[ lower()]out[ ] pig pig pig cow cow pig cow pig salmon namefood using map is convenient way to perform element-wise transformations and other data cleaning-related operations replacing values filling in missing data with the fillna method can be thought of as special case of more general value replacement while mapas you've seen abovecan be used to modify subset of values in an objectreplace provides simpler and more flexible way to do so let' consider this seriesin [ ]data series([ - - - ]in [ ]data out[ ] - - - data wranglingcleantransformmergereshape www it-ebooks info