webinar-strings-jack-tripper-2022-04-02.py

# We once called it "All the Ways to Print"... but printing isn't all we do to strings.
# So we changed it to "String Manipulation and Printing"
# but now it's
# "Your Strings Are Jack Tripper"

# How We Build Strings
# Concatenation - simple, but not the best! Too easy to make a mistake with spaces or punctuation
name = "Sue"
print("My name is " + str(name) + ", how do you do?") # this will wear you out in the long run

# Better!
# string class format()
print("My name is {}, how do you do?".format(name))
# f strings
print(f"My name is {name}, how do you do?")

# print()
print() # 0 arguments to print... well except for the hidden
print(end="\n")
print("Hi.") # one argument

myList = [1, 2, 3, 4]
for num in myList:
    print(num)

# MISTAKE TO AVOID #1:
# If you use the end param of print(), don't forget to make a clean line
# see ZyBooks 2.9
for num in myList:
    print(num, end=" ") # any time we use end, we risk output on the same line later
print() # the fix... make a blank call to print()
print("the next thing I printed")

# Know your WHITESPACE
" " # a space, from hitting the spacebar
# There are also about 20-25 other simple spaces in Unicode
"\n" # new line return
"\r" # carriage return, back to beginning of the current line
"\t" # tab
"\f" # form feed

# MISTAKE TO AVOID #2:
# when our unit testing gets stricter as the course progresses...
# myVar = input()
# myVar = myVar.strip() # string methods to get rid of "extra" whitespace: strip(), lstrip(), rstrip()
# or do it in one step...
# myVar = input().strip()
#
# myVar = int(input())
# myVar = int(input().strip()) # though the int() function itself will ignore whitespace

muppetDict = {
    "Kermit": "the Frog",
    "Fozzy": "the Bear"
}
# Not keys: "Kermit\r", "Kermit\t", "Kermit ", etc
myVar = "Kermit " # <-- not in the dictionary, but it will look much the same as "Kermit"
myVar = myVar.strip() # get rid of stray whitespace characters
if "Kermit" in muppetDict:
    print("Kermit is in the dictionary.")
else:
    print("Nope. Not there.")

if myVar in muppetDict:
    print("Kermit is in the dictionary.")
else:
    print("Nope. Not there.")

# STRINGS
# be able to SLICE
myString = "abcdef"
# slice: myString[start:stop:step]
revString = myString[::-1]
print(revString) # fedbca

# Useful String Methods
# myString.format()
# myString.split() # makes a list of smaller strings
# " ".join(myListOfStrings)
# myString.strip() # lstrip(), rstrip()
# myString.replace("old", "new") # myString.replace("old", "")
# myString.count("subStr") # returns an int
# myString.find("subStr") # return an int index of where it starts, -1 if not there
# myString.isspace() # many "is" methods of the string type
# myString.startswith("subStr")

# help(str)
# print(dir(str))
for item in dir(str):
    if not item.startswith("_"):
        print(item)
# now that you're refreshed yourself with dir(), you can call help() more precisely:
help(str.split)

# Don't assume you need a special module
# Parsing 24 hour time as a string...
myVar = "16:40"
anotherTime = "9:30" # not zero padded
yetAnotherTime = "09:30" # but here it is zero padded
# ... so we don't know whether our hour will be 2 characters/indices or 1...
timeList = yetAnotherTime.split(":")
print(timeList) # ['09', '30']... hour and min!

# or slice it!
# think you can't slice because the : isn't always in the same position?
hour = anotherTime[:anotherTime.find(":")] # <- find() gets us around the problem
print(hour)