# Zhi Yuan "Oscar" Lin # 21 October 2021 # In this lesson, I learned more about the string methods "len()", ".count()", and ".find()" through completing # examples and tasks. I also learned why being a programmer is difficult since there are many rules a programmer # needs to remember. # There were no major problems or questions throughout this lesson.

# [ ] review and run example # The variable "work_tip" is assigned to the string "save your code". work_tip = "save your code" # This function displays the string "number of characters in string" in the output. print("number of characters in string") # This function displays the given value when the string method "len()" determines the length of the value # assigned to the work_tip variable in the output. Additionally, a blank line will be displayed on the next # line of the output due to the escape character "\n". print(len(work_tip),"\n") # This function displays the string 'letter "e" occurrences' in the output. print('letter "e" occurrences') # This function displays the given value when the string method ".count()" determines how many times the character # "e" occurred in the value assigned to the work_tip variable in the output. Additionally, a blank line will be # displayed on the next line of the output due to the escape character "\n". print(work_tip.count("e"),"\n") # This function displays the string "find the index of the first space" in the output. print("find the index of the first space") # This function displays the given value when the string method ".find()" determines the index position of the character " " # in the value assigned to the work_tip variable in the output. # Additionally, a blank line will be displayed on the next line of the output due to the escape character "\n". print(work_tip.find(" "),"\n") # This function displays the string 'find the index of "u" searching a slice work_tip[3:9] -' and the 4th to the # 9th character of the value assigned to the work_tip variable in the output. print('find the index of "u" searching a slice work_tip[3:9] -', work_tip[3:9]) # This function displays the given value when the string method ".find()" determines the index position of the character # "u" from the 4th to the 9th character of the value assigned to the work_tip variable in the output. Additionally, # a blank line will be displayed on the next line of the output due to the escape character "\n". print(work_tip.find("u",3,9),"\n") # This function displays the string 'find the index of "e" searching a slice work_tip[4:] -' and the 5th to the last # character of the value assigned to the work_tip variable in the output. print('find the index of "e" searching a slice work_tip[4:] -', work_tip[4:]) # This function displays the given value when the string method ".find()" determines the index position of the character # "e" from the 5th to the last character of the value assigned to the work_tip variable in the output. print(work_tip.find("e",4))

# [ ] review and run example # The variable "work_tip" is assigned to the string "good code is commented code". work_tip = "good code is commented code" # This function displays the concatenated string formed from the string 'The sentence "', the value assigned to the # work_tip variable, the string '"has character length = "', and the value given when the string method "len()" # determines the length of the value assigned to the work_tip variable, in the output. Additionally, the double quotes # shown in the output are due to the escape character '\"'. print("The sentence: \"" + work_tip + "\" has character length = ", len(work_tip) )

# [ ] review and run example # find the middle index # The variable "work_tip" is assigned to the string "good code is commented code". work_tip = "good code is commented code" # The variable "mid_pt" is assigned to the value of the given value when the string method "len()" determines # the length of the value assigned to the work_tip variable being divided by the integer "2", and converted into an # integer due them being in the parentheses of the int() function. mid_pt = int(len(work_tip)/2) # print 1st half of sentence # This function displays the first half, 1st to 13th, of the characters of the value assigned to the work_tip # variable in the output. print(work_tip[:mid_pt]) # print the 2nd half of sentence # This function displays the second half, 14th to 27th, of the characters of the value assigned to the work_tip variable # in the output. print(work_tip[mid_pt:])

# [ ] review and run example # This function displays the value assigned to the work_tip variable in the output. print(work_tip) # This function displays string "how many w's? " and the given value when the string method ".count()" determines how # many times the character "w" occurred in the value assigned to the work_tip variable, in the output. print("how many w's? ", work_tip.count("w")) # This function displays string "how many o's? " and the given value when the string method ".count()" determines how # many times the character "o" occurred in the value assigned to the work_tip variable, in the output. print("how many o's? ", work_tip.count("o")) # This function displays string "uses 'code', how many times? " and the given value when the string method # ".count()" determines how many times the sub-string "code" occurred in the value assigned to the # work_tip variable, in the output. print("uses 'code', how many times? ", work_tip.count("code"))

# [ ] review and run example # This function displays the first half, 1st to 13th, of the characters of the value assigned to the work_tip # variable in the output. print(work_tip[:mid_pt]) # This function displays the string "# o's in first half" in the output. print("# o's in first half") # This function displays the given value when the string method ".count()" determines how many times the character # "o" occured from the first half, 1st to 13th, of the characters of the value assigned to the work_tip variable, in # the output. print(work_tip[:mid_pt].count("o")) # This function displays a blank line in the output due to the print() function not having an argument. print() # This function displays the second half, 14th to 27th, of the characters of the value assigned to the work_tip variable # in the output. print(work_tip[mid_pt:]) # This function displays the string "# o's in second half" in the output print("# o's in second half") # This function displays the given value when the string method ".count()" determines how many times the character # "o" occured from the second half, 14th to 27th, of the characters of the value assigned to the work_tip variable, # in the output. print(work_tip[mid_pt:].count("o"))

# [ ] review and run example # The variable "work_tip" is assigned to the string "good code has meaningful variable names". work_tip = "good code has meaningful variable names" # This function displays the value assigned to the work_tip variable in the output. print(work_tip) # index where first instance of "code" starts # The variable "code_here" is assigned to the given value when the string method ".find()" determines the index position # of the start of the sub-string "code" in the value assigned to the work_tip variable. code_here = work_tip.find("code") # This function displays the value assigned to the code_here variable and the string '= starting index for "code"' in # the output. print(code_here, '= starting index for "code"')

# [ ] review and run example # set start index = 13 and end index = 33 # This function displays the string 'search for "meaning" in the sub-string:' and the 14th to 33th character of the value # assigned to the work_tip variable. Additionally, a blank line will be displayed on the next line of the output due to # the escape character "\n". print('search for "meaning" in the sub-string:', work_tip[13:33],"\n") # The variable "meaning_here" is assigned to the given when the string method ".find()" determines the index position of # the sub-string "meaning" from the 14th to 33th character of the value assigned to the work_tip variable. meaning_here = work_tip.find("meaning",13,33) # This function displays the string '"meaning" found in work_tip[13:33] sub-string search at index' and the value assigned # to the meaning_here variable. print('"meaning" found in work_tip[13:33] sub-string search at index', meaning_here)

# [ ] review and run example # if .find("o") has No Match, -1 is returned # This function displays the string "work_tip:" and the value assigned to the work_tip variable in the output. print ("work_tip:" , work_tip) # The variable "location" is assigned to the given value when the string method ".find()" determines the index position # of the character "o" in the value assigned to the work_tip variable. location = work_tip.find("o") # keeps looping until location = -1 (no "o" found) # In this case, the while loop is follow by statement "location >= 0". Hence, as long that is true, the codes that # are indented and follow the while loop will be part of the loop. Thus, the loop starts with string "'o' at index =" # and the value assigned to the location variable, that are within the print() function, being display in the output. # Subsequently, the location variable will be reassigned to the next index position of the character "o" after the # first "o" was found. This loop will continue until location >= is false. while location >= 0: print("'o' at index =", location) # find("o", location + 1) looks for a "o" after index the first "o" was found location = work_tip.find("o", location + 1) # This function will display the string "no more o's" in the output. print("no more o's")

# [ ] use len() to find the midpoint of the string # [ ] print the halves on separate lines # The variable "random_tip" is assigned to the string "wear a hat when it rains". random_tip = "wear a hat when it rains" # The variable "mid" is assigned to the value of the given value when the string method "len()" determines # the length of the value assigned to the random_tip variable being divided by the integer "2", and converted into an # integer due them being in the parentheses of the int() function. mid = int(len(random_tip)/2) # This function displays the first half, 1st to 12th, of the characters in the value assigned to the random_tip # variable in the output. print(random_tip[:mid]) # This function displays the second half, 13th to 24th, of the characters in the value assigned to the random_tip # variable in the output. print(random_tip[mid:])

# for letters: "e" and "a" in random_tip # [ ] print letter counts # [ ] BONUS: print which letter is most frequent # The variable "random_tip" is assigned to the string "wear a hat when it rains". random_tip = "wear a hat when it rains" # This function displays the given value when the string method ".count()" determines how many times the character # "e" occurred in the value assigned to the random_tip variable in the output. print(random_tip.count("e")) # This function displays the given value when the string method ".count()" determines how many times the character # "a" occurred in the value assigned to the random_tip variable. print(random_tip.count("a")) # This IF statement if the given value when the given value from the string method ".count()" that determines how # many times the character "e" occurred in the value assigned to the random_tip variable is greater than the given # value from the string method ".count()" determines how many times the character "a" occurred in the value assigned # to the random_tip variable. If true, the string 'The letter "e" is the most frequent', that is within the parentheses # of the print() function, will be display in the output. If false, the program moves on to the else statement with # the string 'The letter "a" is the most frequent', that is within the parentheses of the print() function, being display # in the output. This loop will if random_tip.count("e") > random_tip.count("a"): print('The letter "e" is the most frequent') else: print('The letter "a" is the most frequent')

# [ ] print long_word from the location of the first and second "t" # The variable "long_word" is assigned to the string "juxtaposition". long_word = "juxtaposition" # The variable "location" is assigned to the given value when the string method ".find()" determines the index position # of the character "t" in the value assigned to the long_word variable. location = long_word.find("t") # In this case, the while loop is follow by statement "location >= 0". Hence, as long that is true, the codes that # are indented and follow the while loop will be part of the loop. Thus, the loop starts with string "'t' at index =" # and the value assigned to the location variable, that are within the parentheses of the print() function, being display # in the output. Subsequently, the location variable will be reassigned to the next index position of the character # "t" after the first "t" was found. This loop will continue until location >= is false. while location >= 0: print("'t' at index =", location) location = long_word.find("t", location + 1)

# The variable "quote" is assigned to the string "they stumble who run fast". quote = "they stumble who run fast" # The variable "start" is assigned to the integer "0". start = 0 # The variable "space_index" is assigned to the given value when the string method ".find()" determines the index # position of the character " ". space_index = quote.find(" ") # In this case, the while loop is follow by statement "space_index != -1". Hence, as long that is true, the codes that # are indented and follow the while loop will be part of the loop. Thus, the loop starts with displaying the substring # that is between the index position assigned to the start variable and index position assigned to the space_index variable # in the value assigned to the quote variable, that is between the parentheses of the print() function, being display in # the output. Subsequently,the start variable will be reassigned to the value assigned to the space_index variable # incremented by the integer "1". Additionally, the space_index variable will be reassigned to the give value from the # string method ".find()" that determines the index position for the character " " that is between the index position # assigned to the start variable and the last character. This loop will continue until space_index != -1 is false. while space_index != -1: print(quote[start:space_index]) start = (space_index + 1) space_index = quote.find(" ", start) # This function displays the substring from the index position assigned to the start variable to the last character, in # the output. print(quote[start:])