Adventures in
Python: String Manipulation and
Function/Derivative Table (Subroutines)
String Manipulation
This script demonstrates several string functions:
length: the number of
characters in a string
stringname.replace(‘target
string’,‘new string’): replace a part of
a string
stringname.capitalize():
capitalize the first letter of a string
stringname.split(): splits a string at its spaces
Other string functions:
stringname.lower():
makes all letters of a string to lower case
stringname.upper(): makes all letters of a string to upper case
You can join strings with the plus symbol ( + ).
The nice thing is that you won’t need to import any modules
for the above string functions.
Script:
# program 008
print('Program 008:
String Demo')
str1 = input('Please
type some text. ')
# input defaults to
strings
# length
print('Length')
l = len(str1)
print('Length',l)
# capitalizes the
first letter
print('Capitalize')
str2 =
str1.capitalize()
print(str2)
# string splits at
spaces
print('Split')
str3 = str1.split()
print(str3)
# replacement
str4 = str1
str4 =
str4.replace('a','e')
str4 =
str4.replace('u','a')
str4 =
str4.replace('o','u')
str4 =
str4.replace('i','o')
str4 =
str4.replace('e','i')
print('Can you read
this?')
print(str4)
Output: with the “This
is my demonstration.”
Program
008: String Demo
Please
type some text. This is my demonstration.
Length
Length 25
Capitalize
This is
my demonstration.
Split
['This',
'is', 'my', 'demonstration.']
Can you
read this?
Thos os
my dimunstritoun.
Function/Derivative Table (Subroutines)
You can create user functions (subroutines) in python by the
def structure. You return results by the return command.
Script (you can enter whatever your function you like, I
have imported the math module):
# Program 009 Using
def and creating a table
# import math
import math
def fx(x):
f = math.exp(-x**2/2)
return f;
print('Function
Table')
beg =
float(input('start: '))
end =
float(input('stop: '))
stp =
float(input('step: '))
# loop begins
h = .00001
k = beg
print('k',':','f(x)',';','slope')
while k <= end:
# function
a = fx(k)
# derivative
b = fx(k+h)
c = fx(k-h)
d = (b - c)/(2 * h)
print(k,',',a,',',d)
print('- - - - - - - -')
k = k + stp
Output (with start = 0, stop = 5, step = 1)
Function
Table
start: 0
stop: 5
step: 1
k : f(x)
; slope
0.0 , 1.0
, 0.0
- - - - -
- - -
1.0 ,
0.6065306597126334 , -0.6065306596914066
- - - - -
- - -
2.0 ,
0.1353352832366127 , -0.27067056647955834
- - - - -
- - -
3.0 ,
0.011108996538242306 , -0.033326989618259056
- - - - -
- - -
4.0 ,
0.00033546262790251185 , -0.0013418505118650097
- - - - -
- - -
5.0 ,
3.726653172078671e-06 , -1.8633265866508763e-05
- - - - -
- - -
Eddie
This blog is property of Edward Shore, 2017.
