Changes between Version 55 and Version 56 of ControlSystems/SoftwareTeam/IntroToPython

Timestamp:

Sep 4, 2017, 7:41:53 PM (8 years ago)

Author:

cdelgigante

Comment:

--

ControlSystems/SoftwareTeam/IntroToPython

@@ -206 +206 @@
  * `round(x,[n])`:  Rounds a decimal number x to n digits after the decimal point.  The [] means that the n is optional, if you don't include it, n=0.
  * `sum(iterable)`:  Sums all the numbers in the list ''iterable''.
- * `<string>.isdigit()`:   Strings and some other variable types like lists have some special functions just for them, called methods.  This one returns true of all of the digits in the string are numbers, others are [[https://docs.python.org/3/library/stdtypes.html#string-methods|here]].   '123' would return ''True'', "Cat" would return ''False''. Handy for validation.  You call them *on* the variable itself.
+ * `<string>.isdigit()`:   Strings and some other variable types like lists have some special functions just for them, called methods.  This one returns true of all of the digits in the string are numbers, others are [[https://docs.python.org/3/library/stdtypes.html#string-methods|here]].   '123' would return ''True'', "Cat" would return ''False''. Handy for validation.  You call them *on* the variable itself, and it has to have a value before you can call these methods.
 
 Here's some examples of how they're used (don't forget to look at earlier lessons for range() and print().
@@ -212 +212 @@
 {{{
 #!python
-a=input("Pick a number, any number)
+a=input("Enter a number, any number-->")  # Enter something at the prompt.  Program will wait at this point.
 print(a);
 
 b = pow(2,2)
-print(b) [ticket:4 # Answer is 4]
+print(b) #Result is 4 (2 to the power of 2)
 
 c = round(3.14159, 2)
-print(c) #Answer is 3.14
+print(c) #Result is 3.14
 
 d = sum([1,2,3,4])
-print(d) # Answer is 10
-}}}
-
-You can combine these functions with control structures to do interesting stuff too: 
-{{{
-#!python
+print(d) #Result is 10
+
+e = "123"
+f = e.isdigit()
+print(f) #Result is True
+}}}
+
+Try running these yourself, making sure the results are as expected.
+
+You can even combine these functions with control structures to do some interesting stuff.  For example, try running this (entering values for x and why when prompted.  Try putting in non-numeric values too): 
+
+{{{
+#!python
+x="" # Put a dummy string in x and y so both while-nots below work.  Pretty slick, eh?  Programming uses tricks like this all the time.
+y="" 
 while not x.isdigit():  # Note the "not"...in this case if x is not all digits, run the block of code in the while loop
-   x=input("Enter x")
+   x=input("Enter x-->")
 while not y.isdigit():
-   y=input("Enter y")
+   y=input("Enter y-->")
 z = pow(x,y)
 if z > 100:
@@ -237 +246 @@
 }}}
 
+But wait, there's more...you can create your own functions.  That way if you come up with cool way to do something you dont have to repeat yourself as much.  For instance:
+
+
+
+Now your turn...  In the 'That's-a big number exercise above" make a function called inputNumber, and modify it to use that instead of the while-not stuff.  Much easier to read, no?
+
+
+
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