Appendix B
Quick Reference
Table 1 Python input, output, variables |
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Leaving reminders by using comments |
Using constants |
# whole-line comment print("hello") # end-of-line comment |
SIZE = 100 # upper case name |
Printing to the screen |
Reading from the keyboard (Python V3) |
print(10) # print a number print("hello") # print a string print(a) # print a variable |
name = input("your name?") age = int(input("how old?")) |
Storing values in variables |
Using Boolean variables |
a = 10 # an integer (whole) number b = 20.2 # a decimal number message = "hello" # a string finished = True # a Boolean high_score = None # no value |
anotherGo = True while anotherGo: choice = int(input("choice?")) if choice == 8: anotherGo = False |
Converting strings to (integer) numbers |
Converting numbers to strings |
size = int(size) size = size + 1 |
age = str(age) print("Your age is " + age) |
Calculating with number variables |
Calculating absolute values and differences |
b = a + 1 # addition c = a - 1 # subtraction d = a * 2 # multiplication e = a / 2 # division f = a % 2 # remainder after division |
absolute = abs(-1) # absolute is 1 difference = abs(x1-x2) smallest = min(x1, x2) largest = max(x1, x2) |
Table 2 Python loops |
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Looping |
Using counted loops |
a = 0 while a<100: print(a) a = a + 1 |
for a in range(10): print(a) # 0..9 for a in range(5, 50, 5): print(a) # 5..45 in steps of 5 |
Looping through all characters in a string |
Splitting comma-separated strings |
name = "Charlotte" for ch in name: print(ch) |
line = ... |