iolite Python for LA-ICP-MS Course - Week 2 Discussion

Bence

Hi Everyone,

Great job on the assignments this week. There were some interesting applications, including an uplifting positivity generator, a beer intake monitor, and a caffeination guide. 😀 Some were very spurious (Arsenal finish behind Spurs??? 😄)

This week there is no assignment, but please let us know if you have any questions about the course content, or about last week.

-Bence

sunguochao

Bence Hi Bence, I registered for the course at 11.22, but I haven't received any email. I tried to register again today, but it seems that i can't register now. How can I join the class now?

Bence

Here's one little tip that might be handy given some of the assignments I've seen:

When comparing string (e.g. if myStr == 'Word') python will consider uppercase and lowercase letters to be different.

So if myStr is word it won't match Word. One way to get around this is to use the builtin string function lower(). This will convert the string to all lowercase letters. Here's an example:

myStr = 'Word'

if myStr == 'word':
    print('Found word')     #This won't be printed out

if myStr.lower() == 'word':
   print('Found word')    # This will work, because 'Word' will be converted to 'word'

Some more info here

I hope that helps!

Bence

Hi sunguochao
I have just sent you an email. Please let me know if you don't get it.

-Bence

Chiranjeeb

Hi Bence,

I am learning this whole coding thing for the first time. So it is taking some time for me to understand. I am still in the weeks 2 part. I was wondering if there is any place where I can find the results of the assignments sections which are at the end of each chapter of the Py4e. I am currently stuck at the exercise 2 of the Dictionary lesson. I am struggling to make a dictionary using the selective words (word 3 from each line starting with From) and then use the counting function. I can make the dictionary with every word after splitting, but I only need the "day" from those lines to be counted in the dictionary.

Thanks

Bence

Hi Chiranjeeb,

There are solutions to the exercises here although the numbering is not obvious (it seems that the answer you're looking for is ex 9.2 in the link). However, if you can post your code, I could help point out why it's not working or how to improve it, if that would be better than just providing the solution to the exercise?

-Bence

Chiranjeeb

Hi Bence,

Thanks for the link. It is definitely more useful if you can have a look at the code. I think I was initially thinking the wrong way as I was trying to add things to the dictionary. In stead later I made a list by adding the selective words and then running the for loop to do the counting. Here is what I wrote:

file = open('mbox-short.txt')
D=dict()
L=list()
for line in file:
line = line.rstrip()
if line.startswith('From'):
words = line.split()
if len(words)>3:
L.append(words[2])
print (L)
for x in L:
D[x]= D.get(x,0)+1
print (D)

It seems to be working, but may be there is more elegant ways of doing it.

Thanks, Chiranjeeb

Chiranjeeb

Hi again Bence,

This is another exercise 10.2 from the tuples section. Would you mind having a look at this code as it is not working

file = open('mbox-short.txt')
D=dict()
L=list()
for line in file:
line = line.rstrip()
if line.startswith('From'):
timeofday = line.split()
if len(timeofday)>3:
pos=timeofday[5].find(':')
hour=timeofday[5][:pos]
L.append(hour)

for x in L:
D[x]= D.get(x,0)+1
for key,val in list(D.items()):
L.append((key,val))

L.sort()

for k,v in L:
print (k,v)

Joe

Chiranjeeb

I believe the problem you're having is that your list 'L' contains the strings appended in the first for loop, and tuples appended in the third for loop. So, when you try to sort it, it isn't sure how to compare strings with tuples. You can fix it by resetting the L list just before the third for loop with L = [] or L.clear().

Also note that when posting code on the forum, you can wrap it with ``` at the start and end to keep the code formatting.

file = open('mbox-short.txt')
D=dict()
L=list()
for line in file:
    line = line.rstrip()
    if line.startswith('From'):
        timeofday = line.split()
        if len(timeofday)>3:
            pos=timeofday[5].find(':')
            hour=timeofday[5][:pos]
            L.append(hour)

for x in L:
    D[x]= D.get(x,0)+1

L.clear()
for key,val in list(D.items()):
    L.append((key,val))

L.sort()

for k,v in L:
    print (k,v)

All the best,