S13-Words-for-the-Future-notebooks/python-cheatsheet.ipynb

Python cheatsheet¶

(non-complete, please use, modify, (re)publish!)

In [ ]:

string, integer, float¶

In [ ]:

x = '3'
y = 3
z = 3.5

In [ ]:

type(x)

In [ ]:

type(y)

In [ ]:

type(z)

In [ ]:

print(x * y) # Works

In [ ]:

print(x + y) # Does not work: TypeError

In [ ]:

# From int to str
str(y)

In [ ]:

# From str to int
int(x)

In [ ]:

# From float to int
int(z)

In [ ]:

In [ ]:

In [ ]:

string operations¶

In [ ]:

s = 'hello!'

In [ ]:

s.upper()

In [ ]:

s.lower()

In [ ]:

s.capitalize()

In [ ]:

s.title()

In [ ]:

s.replace('e', 'a')

In [ ]:

s.strip('!')

In [ ]:

s.count('l')

In [ ]:

s.endswith('o')

In [ ]:

s.startswith('h')

In [ ]:

# format a string
name = 'you'
t = 'hello {}'.format(name)
print(t)

In [ ]:

# format a string (different way of writing the same!)
name = 'you'
t = f'hello {name}'
print(t)

In [ ]:

In [ ]:

In [ ]:

In [ ]:

In [ ]:

loops¶

In [ ]:

In [ ]:

In [ ]:

In [ ]:

In [ ]:

lists¶

In [ ]:

# Make an empty list
bag = []

In [ ]:

type(bag)

In [ ]:

# Add items to the list
word = 'hello'
bag.append(word)
print(bag)

In [ ]:

# From list to string
' --- '.join(bag)

In [ ]:

In [ ]:

In [ ]:

In [ ]:

dictionaries¶

In [ ]:

# Make an empty dictionary
dict = {}

In [ ]:

dict['word'] = 10  
print(dict)

In [83]:

dict.keys()

Out[83]:

dict_keys(['word'])

In [ ]:

In [ ]:

In [ ]:

open(), read(), write(), close()¶

mode can be:

• r when the file will only be read
• w for only writing (an existing file with the same name will be erased)
• a opens the file for appending, any data written to the file is automatically added to the end
• r+ opens the file for both reading and writing

(The mode argument is optional: r will be assumed if it’s omitted.)

https://docs.python.org/3/tutorial/inputoutput.html#reading-and-writing-files

In [ ]:

# open(), read()
txt = open('txt/language.txt', 'r').read()
print(txt)

In [ ]:

# readlines()
lines = open('txt/language.txt', 'r').readlines()
print(lines)

In [ ]:

# listdir() (open multiple files in a folder)
import os
folder = 'txt/words-for-the-future/'
for file in os.listdir(folder):
    print(folder+file)
    # txt = open(folder+file).read()
    # print(txt)

In [ ]:

# write() (returns a number, this is how many characters have been written to the file)
out = open('out.txt', 'w')
out.write('Hello!')

In [ ]:

In [ ]:

In [ ]:

In [ ]:

In [ ]:

In [ ]: