16.6: Chapter 7
- Page ID
- 117502
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)7.1 Module basics
- b. The code has ten
defstatements, each of which defines a function. - a. Many modules consist of function definitions only. The functions are intended to be called in other modules.
- c.
area.cube(5)is6 * 5**2, which is6 * 25, which is150. - a. When importing a module from another file, the suffix .py is removed.
- b. The circle function must be called using the area variable that refers to the module.
- b. Adding the function to the area module makes the function easier to reuse in other programs.
7.2 Importing names
- a. This statement imports the sqrt function defined in the math module.
- b. A variable is defined for each function imported: sin, cos, and tan.
- b. A name error occurs when a variable name is not found, which might be due to a missing import statement.
- b. This statement replaces the previously imported circle function, even though
circle()andarea.circle()have different parameters. - a. Assigning the area variable replaces the previously imported module with the integer
51. The variable can no longer be used to call functions in the area module. - b. The most recent definition of
hello()requires one argument, so this line would result in an error.
7.3 Top-level code
- b. Whenever this module is imported, Python will output
"Defining sphere function"as a side effect. - a. Even though nothing is printed, calling the sphere function ten million times causes a delay in the main program.
- a. All code is at the top level, and no functions are defined. Importing this module would run all code as a side effect.
- c. The variable
__name__is the module's name, unless the module was run as the main program. In that case,__name__is"__main__". - a. Since test.py was imported, the value of
__name__is"test". - c. This line is found in many Python modules to check if the module was run as the main program.
7.4 The help function
- b. The digits have 0 red and 0 green, so the color must be a shade of blue. Navy is a darker version of standard blue,
#0000FF. - c. FF in hexadecimal is 255, the maximum amount of red, green, or blue in a color.
- a. The red, green, and blue values for orange are higher than the red, green, and blue values for green.
- b. The hexadecimal for YELLOW is
#FFFF00, meaning 255 red + 255 green + 0 blue. - c. Both the
darkenfunction and theBLUEvariable must be accessed via thecolorsvariable. - a. Function names that begin with an underscore are intended to be used only within the current module.
- b. Only docstrings are included in the documentation. All comments are ignored by the help function.
- a. The functions are sorted alphabetically by name to make looking up a function easier.
- a. Functions that begin with an underscore are intended to be used only within a module, not in other modules.
7.5 Finding modules
- a. This reference describes the standard library, including built-in functions, types, and modules.
- b. As explained in the documentation of the
calendarmodule,MONDAYis0andSUNDAYis6. - a. The
tkintermodule stands for Tk interface. Tk is a standard toolkit for creating windows, text boxes, buttons, and other graphical widgets. - c.
MoviePyis a module for video editing, andPillowis a module for image processing. - a. According to the "Features" section of the documentation,
Arrow's is a "fully-implemented, drop-in replacement fordatetime." - a. This function converts a color code to a color name. Ex:
hex_to_name("#daa520")returns"goldenrod".


