Turn each element of a list into a separate string?

Question

I have the following list:

mylist=[[3, 95],[8, 92],[18, 25],[75, 78],[71, 84],-9999,[96, 50],[91, 70],-9999,[19, 60]]

In it, each element is a list itself, apart from the -9999 values which are int values.

Say that I want to use a for loop to transform each element into a string, in order to write it to an excel or csv file. How could I do it?

Here is my attempt:

mylist=[[3, 95],[8, 92],[18, 25],[75, 78],[71, 84],-9999,[96, 50],[91, 70],-9999,[19, 60]]
for i in enumerate(mylist):
    str1 = ''.join(str(e) for e in mylist)

But what I get is the entire list transformed into a single string, without each item being differentiated:

str1='[3, 95][8, 92][18, 25][75, 78][71, 84]-9999[96, 50][91, 70]-9999[19, 60]'

Instead, I would like this:

str1='[3,95]' #Iter 1
str1='[8, 92]' #Iter 2
str1='[18, 25]' #Iter 3
...
#and so forth

Have a look at 'list comprehensions', docs.python.org/2/tutorial/… — EvertW
– EvertW, Commented Nov 24, 2015 at 11:17

Netwave · Accepted Answer · 2015-11-24 11:27:47Z

5

This should work:

for e in map(str, myList):
    #do your stuff here, e is '[3, 95]' on the fst element and so on

map applies a function to each element in myList. Using the str function will transform each element in your list in a string so you can use it freely.

edited Nov 24, 2015 at 11:27

answered Nov 24, 2015 at 11:22

Netwave

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furas · Accepted Answer · 2015-11-24 11:25:48Z

2

mylist = [[3, 95],[8, 92],[18, 25],[75, 78],[71, 84],-9999,[96, 50],[91, 70],-9999,[19, 60]]

# convert all elements
new_list = [str(e) for e in mylist ]

# use it
for str1 in new_list:
    print str1

or

mylist = [[3, 95],[8, 92],[18, 25],[75, 78],[71, 84],-9999,[96, 50],[91, 70],-9999,[19, 60]]

for x in mylist:
    # convert one element and use it
    str1 = str(x) 
    print str1

answered Nov 24, 2015 at 11:25

furas

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Comments

SuperBiasedMan · Accepted Answer · 2015-11-24 11:24:26Z

1

You've made two separate mistakes here. First, inside each iteration you're using str.join which makes a string from the full list, when you just want str(elem) where elem is the current item in the list.

mylist=[[3, 95],[8, 92],[18, 25],[75, 78],[71, 84],-9999,[96, 50],[91, 70],-9999,[19, 60]]
for elem in mylist:
    str1 = str(elem)

You also used enumerate improperly. enumerate is used to get the index value alongside each item of a list. Your original code took the index and the item both as i. ie. i = (0, [3, 95]), when really you'd want them separate. If you need these indices, use this:

for i, elem in enumerate(mylist):
    str1 = str(elem)

Where i = 0 and elem = [3, 95].

answered Nov 24, 2015 at 11:24

SuperBiasedMan

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2 Comments

FaCoffee Over a year ago

Thank you very much. Precise and concise answer. Also, thanks for pointing out my mistakes.

SuperBiasedMan Over a year ago

@FC84 Glad to help, I'd actually recommend Daniel's approach over mine if you don't need enumerate, as using map saves you a line of code and looks cleaner.

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